I have an external RAID with 10 36GB 15K drives. These drives are only for
the data of the SQL server, not tran logs, tempdb's etc.
Database Type is OLTP with more then 30% writes then reads
This is my question:
I understand more spindles are better, and I understand RAID 10 is faster
for writes then a RAID5 configuration. Plus both configurations will give me
enough HD space. So on with the question.
Should i use RAID 10 or RAID5?
RAID 10 would give be theoretically faster writes and great protection, but
gives me only 5 disks to write to simultaneously.
RAID 5 gives me around 9 disks but is known to be slower due to the
overhead.
Is the RAID5 really that much slower that it would hinder performance
compared to a RAID 10 with only 5 disks?
So what do you guys think?
-King
yes.
go RAID 1+0
If you have time you can test this with a handful of IOStress test
utilities.
you could also talk directly to your vendor.
As I learned today, you will also want to maximize the WRITE Cache on the
RAID Controller(s).
Cheers
Greg Jackson
PDX, Oregon
|||Hi
Where are the transaction logs going? They are as critical to the Db as the
data files.
RAID-10 wins hands down. RAID-5 has just too much overhead for the parity.
From a safety perspective, on RAID-5, you loose 2 drives, bye bye data.
RAID -10 can lose half it's drives, as long as it is never both pairs of a
mirror.
So performance wins.
Regards
Mike Epprecht, Microsoft SQL Server MVP
Zurich, Switzerland
IM: mike@.epprecht.net
MVP Program: http://www.microsoft.com/mvp
Blog: http://www.msmvps.com/epprecht/
"news.microsoft.com" <richk@.bluestreammedia.com> wrote in message
news:OUGbB56EFHA.2176@.TK2MSFTNGP15.phx.gbl...
> I have an external RAID with 10 36GB 15K drives. These drives are only
for
> the data of the SQL server, not tran logs, tempdb's etc.
> Database Type is OLTP with more then 30% writes then reads
> This is my question:
> I understand more spindles are better, and I understand RAID 10 is faster
> for writes then a RAID5 configuration. Plus both configurations will give
me
> enough HD space. So on with the question.
> Should i use RAID 10 or RAID5?
> RAID 10 would give be theoretically faster writes and great protection,
but
> gives me only 5 disks to write to simultaneously.
> RAID 5 gives me around 9 disks but is known to be slower due to the
> overhead.
> Is the RAID5 really that much slower that it would hinder performance
> compared to a RAID 10 with only 5 disks?
> So what do you guys think?
>
> -King
>
|||Hi
Yes, have write cache, as long as the RAID card has battery backup. If not,
kiss your data goodbye as you will have some decent corruption.
For us, data security over performance, so write caching is off.
Regards
Mike Epprecht, Microsoft SQL Server MVP
Zurich, Switzerland
IM: mike@.epprecht.net
MVP Program: http://www.microsoft.com/mvp
Blog: http://www.msmvps.com/epprecht/
"pdxJaxon" <GregoryAJackson@.Hotmail.com> wrote in message
news:#62vk86EFHA.1264@.TK2MSFTNGP12.phx.gbl...
> yes.
> go RAID 1+0
> If you have time you can test this with a handful of IOStress test
> utilities.
> you could also talk directly to your vendor.
> As I learned today, you will also want to maximize the WRITE Cache on the
> RAID Controller(s).
>
> Cheers
> Greg Jackson
> PDX, Oregon
>
|||yes....HEAVENS YES.
One needs "battery backed" Cache.
GAJ
|||"Mike Epprecht (SQL MVP)" <mike@.epprecht.net> wrote in message
news:%23qs9yC7EFHA.2540@.TK2MSFTNGP09.phx.gbl...
> Hi
> Yes, have write cache, as long as the RAID card has battery backup. If
not,
> kiss your data goodbye as you will have some decent corruption.
>
Yes we have a 72-hour backup on all RAID controllers
[vbcol=seagreen]
> For us, data security over performance, so write caching is off.
> Regards
> --
> Mike Epprecht, Microsoft SQL Server MVP
> Zurich, Switzerland
> IM: mike@.epprecht.net
> MVP Program: http://www.microsoft.com/mvp
> Blog: http://www.msmvps.com/epprecht/
> "pdxJaxon" <GregoryAJackson@.Hotmail.com> wrote in message
> news:#62vk86EFHA.1264@.TK2MSFTNGP12.phx.gbl...
the
>
|||"Mike Epprecht (SQL MVP)" <mike@.epprecht.net> wrote in message
news:e4EdmB7EFHA.4004@.tk2msftngp13.phx.gbl...
> Hi
> Where are the transaction logs going? They are as critical to the Db as
the
> data files.
> RAID-10 wins hands down. RAID-5 has just too much overhead for the parity.
> From a safety perspective, on RAID-5, you loose 2 drives, bye bye data.
> RAID -10 can lose half it's drives, as long as it is never both pairs of a
> mirror.
> So performance wins.
Mike,
Thanks! Thats what i thought.. but what puzzled me was the spindols. Since
the RAID5 configuration would have more drives to spread the write acrossed
then the RAID 1+0 i wasn't sure if it mattered. Keep in mind i haven't got
the hardware yet... so no testing has been done. and yes i will do testing.
thanks for your input.
-King
[vbcol=seagreen]
> Regards
> --
> Mike Epprecht, Microsoft SQL Server MVP
> Zurich, Switzerland
> IM: mike@.epprecht.net
> MVP Program: http://www.microsoft.com/mvp
> Blog: http://www.msmvps.com/epprecht/
> "news.microsoft.com" <richk@.bluestreammedia.com> wrote in message
> news:OUGbB56EFHA.2176@.TK2MSFTNGP15.phx.gbl...
> for
faster[vbcol=seagreen]
give
> me
> but
>
|||In a Raid 1+0 you can't look at it as only x many drives to write to. In
your case you 10 drives that are configured as such. 5 Mirrored pairs that
are striped in a Raid 0 configuration. Yes that means you have to split the
data 5 ways vs. 9 for the Raid 5 but each split goes to a mirrored pair. The
mirrored pair has the option to read from one disk and write to the other,
write to both, read from both etc. It can be smart in how it reads and
writes to the mirrored pair. That plus the fact it doe not have to
calculate parity is a fast combination.
Andrew J. Kelly SQL MVP
"news.microsoft.com" <richk@.bluestreammedia.com> wrote in message
news:%23qHC657EFHA.3672@.TK2MSFTNGP14.phx.gbl...
> "Mike Epprecht (SQL MVP)" <mike@.epprecht.net> wrote in message
> news:e4EdmB7EFHA.4004@.tk2msftngp13.phx.gbl...
> the
> Mike,
> Thanks! Thats what i thought.. but what puzzled me was the spindols.
> Since
> the RAID5 configuration would have more drives to spread the write
> acrossed
> then the RAID 1+0 i wasn't sure if it mattered. Keep in mind i haven't
> got
> the hardware yet... so no testing has been done. and yes i will do
> testing.
> thanks for your input.
> -King
>
> faster
> give
>
|||This website has great details and arguments why you should not use RAID 5
for a RDBMS implementation
http://www.baarf.com/
GertD@.SQLDev.Net
Please reply only to the newsgroups.
This posting is provided "AS IS" with no warranties, and confers no rights.
You assume all risk for your use.
Copyright SQLDev.Net 1991-2005 All rights reserved.
"news.microsoft.com" <richk@.bluestreammedia.com> wrote in message
news:OUGbB56EFHA.2176@.TK2MSFTNGP15.phx.gbl...
>I have an external RAID with 10 36GB 15K drives. These drives are only for
> the data of the SQL server, not tran logs, tempdb's etc.
> Database Type is OLTP with more then 30% writes then reads
> This is my question:
> I understand more spindles are better, and I understand RAID 10 is faster
> for writes then a RAID5 configuration. Plus both configurations will give
> me
> enough HD space. So on with the question.
> Should i use RAID 10 or RAID5?
> RAID 10 would give be theoretically faster writes and great protection,
> but
> gives me only 5 disks to write to simultaneously.
> RAID 5 gives me around 9 disks but is known to be slower due to the
> overhead.
> Is the RAID5 really that much slower that it would hinder performance
> compared to a RAID 10 with only 5 disks?
> So what do you guys think?
>
> -King
>
Showing posts with label drives. Show all posts
Showing posts with label drives. Show all posts
Wednesday, March 28, 2012
RAID 10 vs. RAID 5 question
I have an external RAID with 10 36GB 15K drives. These drives are only for
the data of the SQL server, not tran logs, tempdb's etc.
Database Type is OLTP with more then 30% writes then reads
This is my question:
I understand more spindles are better, and I understand RAID 10 is faster
for writes then a RAID5 configuration. Plus both configurations will give me
enough HD space. So on with the question.
Should i use RAID 10 or RAID5?
RAID 10 would give be theoretically faster writes and great protection, but
gives me only 5 disks to write to simultaneously.
RAID 5 gives me around 9 disks but is known to be slower due to the
overhead.
Is the RAID5 really that much slower that it would hinder performance
compared to a RAID 10 with only 5 disks?
So what do you guys think?
-Kingyes.
go RAID 1+0
If you have time you can test this with a handful of IOStress test
utilities.
you could also talk directly to your vendor.
As I learned today, you will also want to maximize the WRITE Cache on the
RAID Controller(s).
Cheers
Greg Jackson
PDX, Oregon|||Hi
Where are the transaction logs going? They are as critical to the Db as the
data files.
RAID-10 wins hands down. RAID-5 has just too much overhead for the parity.
From a safety perspective, on RAID-5, you loose 2 drives, bye bye data.
RAID -10 can lose half it's drives, as long as it is never both pairs of a
mirror.
So performance wins.
Regards
--
Mike Epprecht, Microsoft SQL Server MVP
Zurich, Switzerland
IM: mike@.epprecht.net
MVP Program: http://www.microsoft.com/mvp
Blog: http://www.msmvps.com/epprecht/
"news.microsoft.com" <richk@.bluestreammedia.com> wrote in message
news:OUGbB56EFHA.2176@.TK2MSFTNGP15.phx.gbl...
> I have an external RAID with 10 36GB 15K drives. These drives are only
for
> the data of the SQL server, not tran logs, tempdb's etc.
> Database Type is OLTP with more then 30% writes then reads
> This is my question:
> I understand more spindles are better, and I understand RAID 10 is faster
> for writes then a RAID5 configuration. Plus both configurations will give
me
> enough HD space. So on with the question.
> Should i use RAID 10 or RAID5?
> RAID 10 would give be theoretically faster writes and great protection,
but
> gives me only 5 disks to write to simultaneously.
> RAID 5 gives me around 9 disks but is known to be slower due to the
> overhead.
> Is the RAID5 really that much slower that it would hinder performance
> compared to a RAID 10 with only 5 disks?
> So what do you guys think?
>
> -King
>|||Hi
Yes, have write cache, as long as the RAID card has battery backup. If not,
kiss your data goodbye as you will have some decent corruption.
For us, data security over performance, so write caching is off.
Regards
--
Mike Epprecht, Microsoft SQL Server MVP
Zurich, Switzerland
IM: mike@.epprecht.net
MVP Program: http://www.microsoft.com/mvp
Blog: http://www.msmvps.com/epprecht/
"pdxJaxon" <GregoryAJackson@.Hotmail.com> wrote in message
news:#62vk86EFHA.1264@.TK2MSFTNGP12.phx.gbl...
> yes.
> go RAID 1+0
> If you have time you can test this with a handful of IOStress test
> utilities.
> you could also talk directly to your vendor.
> As I learned today, you will also want to maximize the WRITE Cache on the
> RAID Controller(s).
>
> Cheers
> Greg Jackson
> PDX, Oregon
>|||yes....HEAVENS YES.
One needs "battery backed" Cache.
GAJ|||"Mike Epprecht (SQL MVP)" <mike@.epprecht.net> wrote in message
news:%23qs9yC7EFHA.2540@.TK2MSFTNGP09.phx.gbl...
> Hi
> Yes, have write cache, as long as the RAID card has battery backup. If
not,
> kiss your data goodbye as you will have some decent corruption.
>
Yes we have a 72-hour backup on all RAID controllers
> For us, data security over performance, so write caching is off.
> Regards
> --
> Mike Epprecht, Microsoft SQL Server MVP
> Zurich, Switzerland
> IM: mike@.epprecht.net
> MVP Program: http://www.microsoft.com/mvp
> Blog: http://www.msmvps.com/epprecht/
> "pdxJaxon" <GregoryAJackson@.Hotmail.com> wrote in message
> news:#62vk86EFHA.1264@.TK2MSFTNGP12.phx.gbl...
the[vbcol=seagreen]
>|||"Mike Epprecht (SQL MVP)" <mike@.epprecht.net> wrote in message
news:e4EdmB7EFHA.4004@.tk2msftngp13.phx.gbl...
> Hi
> Where are the transaction logs going? They are as critical to the Db as
the
> data files.
> RAID-10 wins hands down. RAID-5 has just too much overhead for the parity.
> From a safety perspective, on RAID-5, you loose 2 drives, bye bye data.
> RAID -10 can lose half it's drives, as long as it is never both pairs of a
> mirror.
> So performance wins.
Mike,
Thanks! Thats what i thought.. but what puzzled me was the spindols. Since
the RAID5 configuration would have more drives to spread the write acrossed
then the RAID 1+0 i wasn't sure if it mattered. Keep in mind i haven't got
the hardware yet... so no testing has been done. and yes i will do testing.
thanks for your input.
-King
> Regards
> --
> Mike Epprecht, Microsoft SQL Server MVP
> Zurich, Switzerland
> IM: mike@.epprecht.net
> MVP Program: http://www.microsoft.com/mvp
> Blog: http://www.msmvps.com/epprecht/
> "news.microsoft.com" <richk@.bluestreammedia.com> wrote in message
> news:OUGbB56EFHA.2176@.TK2MSFTNGP15.phx.gbl...
> for
faster[vbcol=seagreen]
give[vbcol=seagreen]
> me
> but
>|||In a Raid 1+0 you can't look at it as only x many drives to write to. In
your case you 10 drives that are configured as such. 5 Mirrored pairs that
are striped in a Raid 0 configuration. Yes that means you have to split the
data 5 ways vs. 9 for the Raid 5 but each split goes to a mirrored pair. The
mirrored pair has the option to read from one disk and write to the other,
write to both, read from both etc. It can be smart in how it reads and
writes to the mirrored pair. That plus the fact it doe not have to
calculate parity is a fast combination.
Andrew J. Kelly SQL MVP
"news.microsoft.com" <richk@.bluestreammedia.com> wrote in message
news:%23qHC657EFHA.3672@.TK2MSFTNGP14.phx.gbl...
> "Mike Epprecht (SQL MVP)" <mike@.epprecht.net> wrote in message
> news:e4EdmB7EFHA.4004@.tk2msftngp13.phx.gbl...
> the
> Mike,
> Thanks! Thats what i thought.. but what puzzled me was the spindols.
> Since
> the RAID5 configuration would have more drives to spread the write
> acrossed
> then the RAID 1+0 i wasn't sure if it mattered. Keep in mind i haven't
> got
> the hardware yet... so no testing has been done. and yes i will do
> testing.
> thanks for your input.
> -King
>
> faster
> give
>|||This website has great details and arguments why you should not use RAID 5
for a RDBMS implementation
http://www.baarf.com/
GertD@.SQLDev.Net
Please reply only to the newsgroups.
This posting is provided "AS IS" with no warranties, and confers no rights.
You assume all risk for your use.
Copyright SQLDev.Net 1991-2005 All rights reserved.
"news.microsoft.com" <richk@.bluestreammedia.com> wrote in message
news:OUGbB56EFHA.2176@.TK2MSFTNGP15.phx.gbl...
>I have an external RAID with 10 36GB 15K drives. These drives are only for
> the data of the SQL server, not tran logs, tempdb's etc.
> Database Type is OLTP with more then 30% writes then reads
> This is my question:
> I understand more spindles are better, and I understand RAID 10 is faster
> for writes then a RAID5 configuration. Plus both configurations will give
> me
> enough HD space. So on with the question.
> Should i use RAID 10 or RAID5?
> RAID 10 would give be theoretically faster writes and great protection,
> but
> gives me only 5 disks to write to simultaneously.
> RAID 5 gives me around 9 disks but is known to be slower due to the
> overhead.
> Is the RAID5 really that much slower that it would hinder performance
> compared to a RAID 10 with only 5 disks?
> So what do you guys think?
>
> -King
>
the data of the SQL server, not tran logs, tempdb's etc.
Database Type is OLTP with more then 30% writes then reads
This is my question:
I understand more spindles are better, and I understand RAID 10 is faster
for writes then a RAID5 configuration. Plus both configurations will give me
enough HD space. So on with the question.
Should i use RAID 10 or RAID5?
RAID 10 would give be theoretically faster writes and great protection, but
gives me only 5 disks to write to simultaneously.
RAID 5 gives me around 9 disks but is known to be slower due to the
overhead.
Is the RAID5 really that much slower that it would hinder performance
compared to a RAID 10 with only 5 disks?
So what do you guys think?
-Kingyes.
go RAID 1+0
If you have time you can test this with a handful of IOStress test
utilities.
you could also talk directly to your vendor.
As I learned today, you will also want to maximize the WRITE Cache on the
RAID Controller(s).
Cheers
Greg Jackson
PDX, Oregon|||Hi
Where are the transaction logs going? They are as critical to the Db as the
data files.
RAID-10 wins hands down. RAID-5 has just too much overhead for the parity.
From a safety perspective, on RAID-5, you loose 2 drives, bye bye data.
RAID -10 can lose half it's drives, as long as it is never both pairs of a
mirror.
So performance wins.
Regards
--
Mike Epprecht, Microsoft SQL Server MVP
Zurich, Switzerland
IM: mike@.epprecht.net
MVP Program: http://www.microsoft.com/mvp
Blog: http://www.msmvps.com/epprecht/
"news.microsoft.com" <richk@.bluestreammedia.com> wrote in message
news:OUGbB56EFHA.2176@.TK2MSFTNGP15.phx.gbl...
> I have an external RAID with 10 36GB 15K drives. These drives are only
for
> the data of the SQL server, not tran logs, tempdb's etc.
> Database Type is OLTP with more then 30% writes then reads
> This is my question:
> I understand more spindles are better, and I understand RAID 10 is faster
> for writes then a RAID5 configuration. Plus both configurations will give
me
> enough HD space. So on with the question.
> Should i use RAID 10 or RAID5?
> RAID 10 would give be theoretically faster writes and great protection,
but
> gives me only 5 disks to write to simultaneously.
> RAID 5 gives me around 9 disks but is known to be slower due to the
> overhead.
> Is the RAID5 really that much slower that it would hinder performance
> compared to a RAID 10 with only 5 disks?
> So what do you guys think?
>
> -King
>|||Hi
Yes, have write cache, as long as the RAID card has battery backup. If not,
kiss your data goodbye as you will have some decent corruption.
For us, data security over performance, so write caching is off.
Regards
--
Mike Epprecht, Microsoft SQL Server MVP
Zurich, Switzerland
IM: mike@.epprecht.net
MVP Program: http://www.microsoft.com/mvp
Blog: http://www.msmvps.com/epprecht/
"pdxJaxon" <GregoryAJackson@.Hotmail.com> wrote in message
news:#62vk86EFHA.1264@.TK2MSFTNGP12.phx.gbl...
> yes.
> go RAID 1+0
> If you have time you can test this with a handful of IOStress test
> utilities.
> you could also talk directly to your vendor.
> As I learned today, you will also want to maximize the WRITE Cache on the
> RAID Controller(s).
>
> Cheers
> Greg Jackson
> PDX, Oregon
>|||yes....HEAVENS YES.
One needs "battery backed" Cache.
GAJ|||"Mike Epprecht (SQL MVP)" <mike@.epprecht.net> wrote in message
news:%23qs9yC7EFHA.2540@.TK2MSFTNGP09.phx.gbl...
> Hi
> Yes, have write cache, as long as the RAID card has battery backup. If
not,
> kiss your data goodbye as you will have some decent corruption.
>
Yes we have a 72-hour backup on all RAID controllers
> For us, data security over performance, so write caching is off.
> Regards
> --
> Mike Epprecht, Microsoft SQL Server MVP
> Zurich, Switzerland
> IM: mike@.epprecht.net
> MVP Program: http://www.microsoft.com/mvp
> Blog: http://www.msmvps.com/epprecht/
> "pdxJaxon" <GregoryAJackson@.Hotmail.com> wrote in message
> news:#62vk86EFHA.1264@.TK2MSFTNGP12.phx.gbl...
the[vbcol=seagreen]
>|||"Mike Epprecht (SQL MVP)" <mike@.epprecht.net> wrote in message
news:e4EdmB7EFHA.4004@.tk2msftngp13.phx.gbl...
> Hi
> Where are the transaction logs going? They are as critical to the Db as
the
> data files.
> RAID-10 wins hands down. RAID-5 has just too much overhead for the parity.
> From a safety perspective, on RAID-5, you loose 2 drives, bye bye data.
> RAID -10 can lose half it's drives, as long as it is never both pairs of a
> mirror.
> So performance wins.
Mike,
Thanks! Thats what i thought.. but what puzzled me was the spindols. Since
the RAID5 configuration would have more drives to spread the write acrossed
then the RAID 1+0 i wasn't sure if it mattered. Keep in mind i haven't got
the hardware yet... so no testing has been done. and yes i will do testing.
thanks for your input.
-King
> Regards
> --
> Mike Epprecht, Microsoft SQL Server MVP
> Zurich, Switzerland
> IM: mike@.epprecht.net
> MVP Program: http://www.microsoft.com/mvp
> Blog: http://www.msmvps.com/epprecht/
> "news.microsoft.com" <richk@.bluestreammedia.com> wrote in message
> news:OUGbB56EFHA.2176@.TK2MSFTNGP15.phx.gbl...
> for
faster[vbcol=seagreen]
give[vbcol=seagreen]
> me
> but
>|||In a Raid 1+0 you can't look at it as only x many drives to write to. In
your case you 10 drives that are configured as such. 5 Mirrored pairs that
are striped in a Raid 0 configuration. Yes that means you have to split the
data 5 ways vs. 9 for the Raid 5 but each split goes to a mirrored pair. The
mirrored pair has the option to read from one disk and write to the other,
write to both, read from both etc. It can be smart in how it reads and
writes to the mirrored pair. That plus the fact it doe not have to
calculate parity is a fast combination.
Andrew J. Kelly SQL MVP
"news.microsoft.com" <richk@.bluestreammedia.com> wrote in message
news:%23qHC657EFHA.3672@.TK2MSFTNGP14.phx.gbl...
> "Mike Epprecht (SQL MVP)" <mike@.epprecht.net> wrote in message
> news:e4EdmB7EFHA.4004@.tk2msftngp13.phx.gbl...
> the
> Mike,
> Thanks! Thats what i thought.. but what puzzled me was the spindols.
> Since
> the RAID5 configuration would have more drives to spread the write
> acrossed
> then the RAID 1+0 i wasn't sure if it mattered. Keep in mind i haven't
> got
> the hardware yet... so no testing has been done. and yes i will do
> testing.
> thanks for your input.
> -King
>
> faster
> give
>|||This website has great details and arguments why you should not use RAID 5
for a RDBMS implementation
http://www.baarf.com/
GertD@.SQLDev.Net
Please reply only to the newsgroups.
This posting is provided "AS IS" with no warranties, and confers no rights.
You assume all risk for your use.
Copyright SQLDev.Net 1991-2005 All rights reserved.
"news.microsoft.com" <richk@.bluestreammedia.com> wrote in message
news:OUGbB56EFHA.2176@.TK2MSFTNGP15.phx.gbl...
>I have an external RAID with 10 36GB 15K drives. These drives are only for
> the data of the SQL server, not tran logs, tempdb's etc.
> Database Type is OLTP with more then 30% writes then reads
> This is my question:
> I understand more spindles are better, and I understand RAID 10 is faster
> for writes then a RAID5 configuration. Plus both configurations will give
> me
> enough HD space. So on with the question.
> Should i use RAID 10 or RAID5?
> RAID 10 would give be theoretically faster writes and great protection,
> but
> gives me only 5 disks to write to simultaneously.
> RAID 5 gives me around 9 disks but is known to be slower due to the
> overhead.
> Is the RAID5 really that much slower that it would hinder performance
> compared to a RAID 10 with only 5 disks?
> So what do you guys think?
>
> -King
>
RAID 10 vs. RAID 5 question
I have an external RAID with 10 36GB 15K drives. These drives are only for
the data of the SQL server, not tran logs, tempdb's etc.
Database Type is OLTP with more then 30% writes then reads
This is my question:
I understand more spindles are better, and I understand RAID 10 is faster
for writes then a RAID5 configuration. Plus both configurations will give me
enough HD space. So on with the question.
Should i use RAID 10 or RAID5?
RAID 10 would give be theoretically faster writes and great protection, but
gives me only 5 disks to write to simultaneously.
RAID 5 gives me around 9 disks but is known to be slower due to the
overhead.
Is the RAID5 really that much slower that it would hinder performance
compared to a RAID 10 with only 5 disks?
So what do you guys think?
-Kingyes.
go RAID 1+0
If you have time you can test this with a handful of IOStress test
utilities.
you could also talk directly to your vendor.
As I learned today, you will also want to maximize the WRITE Cache on the
RAID Controller(s).
Cheers
Greg Jackson
PDX, Oregon|||Hi
Where are the transaction logs going? They are as critical to the Db as the
data files.
RAID-10 wins hands down. RAID-5 has just too much overhead for the parity.
From a safety perspective, on RAID-5, you loose 2 drives, bye bye data.
RAID -10 can lose half it's drives, as long as it is never both pairs of a
mirror.
So performance wins.
Regards
--
Mike Epprecht, Microsoft SQL Server MVP
Zurich, Switzerland
IM: mike@.epprecht.net
MVP Program: http://www.microsoft.com/mvp
Blog: http://www.msmvps.com/epprecht/
"news.microsoft.com" <richk@.bluestreammedia.com> wrote in message
news:OUGbB56EFHA.2176@.TK2MSFTNGP15.phx.gbl...
> I have an external RAID with 10 36GB 15K drives. These drives are only
for
> the data of the SQL server, not tran logs, tempdb's etc.
> Database Type is OLTP with more then 30% writes then reads
> This is my question:
> I understand more spindles are better, and I understand RAID 10 is faster
> for writes then a RAID5 configuration. Plus both configurations will give
me
> enough HD space. So on with the question.
> Should i use RAID 10 or RAID5?
> RAID 10 would give be theoretically faster writes and great protection,
but
> gives me only 5 disks to write to simultaneously.
> RAID 5 gives me around 9 disks but is known to be slower due to the
> overhead.
> Is the RAID5 really that much slower that it would hinder performance
> compared to a RAID 10 with only 5 disks?
> So what do you guys think?
>
> -King
>|||Hi
Yes, have write cache, as long as the RAID card has battery backup. If not,
kiss your data goodbye as you will have some decent corruption.
For us, data security over performance, so write caching is off.
Regards
--
Mike Epprecht, Microsoft SQL Server MVP
Zurich, Switzerland
IM: mike@.epprecht.net
MVP Program: http://www.microsoft.com/mvp
Blog: http://www.msmvps.com/epprecht/
"pdxJaxon" <GregoryAJackson@.Hotmail.com> wrote in message
news:#62vk86EFHA.1264@.TK2MSFTNGP12.phx.gbl...
> yes.
> go RAID 1+0
> If you have time you can test this with a handful of IOStress test
> utilities.
> you could also talk directly to your vendor.
> As I learned today, you will also want to maximize the WRITE Cache on the
> RAID Controller(s).
>
> Cheers
> Greg Jackson
> PDX, Oregon
>|||yes....HEAVENS YES.
One needs "battery backed" Cache.
GAJ|||"Mike Epprecht (SQL MVP)" <mike@.epprecht.net> wrote in message
news:%23qs9yC7EFHA.2540@.TK2MSFTNGP09.phx.gbl...
> Hi
> Yes, have write cache, as long as the RAID card has battery backup. If
not,
> kiss your data goodbye as you will have some decent corruption.
>
Yes we have a 72-hour backup on all RAID controllers
> For us, data security over performance, so write caching is off.
> Regards
> --
> Mike Epprecht, Microsoft SQL Server MVP
> Zurich, Switzerland
> IM: mike@.epprecht.net
> MVP Program: http://www.microsoft.com/mvp
> Blog: http://www.msmvps.com/epprecht/
> "pdxJaxon" <GregoryAJackson@.Hotmail.com> wrote in message
> news:#62vk86EFHA.1264@.TK2MSFTNGP12.phx.gbl...
> > yes.
> >
> > go RAID 1+0
> >
> > If you have time you can test this with a handful of IOStress test
> > utilities.
> >
> > you could also talk directly to your vendor.
> >
> > As I learned today, you will also want to maximize the WRITE Cache on
the
> > RAID Controller(s).
> >
> >
> > Cheers
> >
> > Greg Jackson
> > PDX, Oregon
> >
> >
>|||"Mike Epprecht (SQL MVP)" <mike@.epprecht.net> wrote in message
news:e4EdmB7EFHA.4004@.tk2msftngp13.phx.gbl...
> Hi
> Where are the transaction logs going? They are as critical to the Db as
the
> data files.
> RAID-10 wins hands down. RAID-5 has just too much overhead for the parity.
> From a safety perspective, on RAID-5, you loose 2 drives, bye bye data.
> RAID -10 can lose half it's drives, as long as it is never both pairs of a
> mirror.
> So performance wins.
Mike,
Thanks! Thats what i thought.. but what puzzled me was the spindols. Since
the RAID5 configuration would have more drives to spread the write acrossed
then the RAID 1+0 i wasn't sure if it mattered. Keep in mind i haven't got
the hardware yet... so no testing has been done. and yes i will do testing.
thanks for your input.
-King
> Regards
> --
> Mike Epprecht, Microsoft SQL Server MVP
> Zurich, Switzerland
> IM: mike@.epprecht.net
> MVP Program: http://www.microsoft.com/mvp
> Blog: http://www.msmvps.com/epprecht/
> "news.microsoft.com" <richk@.bluestreammedia.com> wrote in message
> news:OUGbB56EFHA.2176@.TK2MSFTNGP15.phx.gbl...
> > I have an external RAID with 10 36GB 15K drives. These drives are only
> for
> > the data of the SQL server, not tran logs, tempdb's etc.
> >
> > Database Type is OLTP with more then 30% writes then reads
> >
> > This is my question:
> >
> > I understand more spindles are better, and I understand RAID 10 is
faster
> > for writes then a RAID5 configuration. Plus both configurations will
give
> me
> > enough HD space. So on with the question.
> >
> > Should i use RAID 10 or RAID5?
> >
> > RAID 10 would give be theoretically faster writes and great protection,
> but
> > gives me only 5 disks to write to simultaneously.
> >
> > RAID 5 gives me around 9 disks but is known to be slower due to the
> > overhead.
> >
> > Is the RAID5 really that much slower that it would hinder performance
> > compared to a RAID 10 with only 5 disks?
> >
> > So what do you guys think?
> >
> >
> > -King
> >
> >
>|||In a Raid 1+0 you can't look at it as only x many drives to write to. In
your case you 10 drives that are configured as such. 5 Mirrored pairs that
are striped in a Raid 0 configuration. Yes that means you have to split the
data 5 ways vs. 9 for the Raid 5 but each split goes to a mirrored pair. The
mirrored pair has the option to read from one disk and write to the other,
write to both, read from both etc. It can be smart in how it reads and
writes to the mirrored pair. That plus the fact it doe not have to
calculate parity is a fast combination.
--
Andrew J. Kelly SQL MVP
"news.microsoft.com" <richk@.bluestreammedia.com> wrote in message
news:%23qHC657EFHA.3672@.TK2MSFTNGP14.phx.gbl...
> "Mike Epprecht (SQL MVP)" <mike@.epprecht.net> wrote in message
> news:e4EdmB7EFHA.4004@.tk2msftngp13.phx.gbl...
>> Hi
>> Where are the transaction logs going? They are as critical to the Db as
> the
>> data files.
>> RAID-10 wins hands down. RAID-5 has just too much overhead for the
>> parity.
>> From a safety perspective, on RAID-5, you loose 2 drives, bye bye data.
>> RAID -10 can lose half it's drives, as long as it is never both pairs of
>> a
>> mirror.
>> So performance wins.
> Mike,
> Thanks! Thats what i thought.. but what puzzled me was the spindols.
> Since
> the RAID5 configuration would have more drives to spread the write
> acrossed
> then the RAID 1+0 i wasn't sure if it mattered. Keep in mind i haven't
> got
> the hardware yet... so no testing has been done. and yes i will do
> testing.
> thanks for your input.
> -King
>
>> Regards
>> --
>> Mike Epprecht, Microsoft SQL Server MVP
>> Zurich, Switzerland
>> IM: mike@.epprecht.net
>> MVP Program: http://www.microsoft.com/mvp
>> Blog: http://www.msmvps.com/epprecht/
>> "news.microsoft.com" <richk@.bluestreammedia.com> wrote in message
>> news:OUGbB56EFHA.2176@.TK2MSFTNGP15.phx.gbl...
>> > I have an external RAID with 10 36GB 15K drives. These drives are only
>> for
>> > the data of the SQL server, not tran logs, tempdb's etc.
>> >
>> > Database Type is OLTP with more then 30% writes then reads
>> >
>> > This is my question:
>> >
>> > I understand more spindles are better, and I understand RAID 10 is
> faster
>> > for writes then a RAID5 configuration. Plus both configurations will
> give
>> me
>> > enough HD space. So on with the question.
>> >
>> > Should i use RAID 10 or RAID5?
>> >
>> > RAID 10 would give be theoretically faster writes and great protection,
>> but
>> > gives me only 5 disks to write to simultaneously.
>> >
>> > RAID 5 gives me around 9 disks but is known to be slower due to the
>> > overhead.
>> >
>> > Is the RAID5 really that much slower that it would hinder performance
>> > compared to a RAID 10 with only 5 disks?
>> >
>> > So what do you guys think?
>> >
>> >
>> > -King
>> >
>> >
>>
>|||This website has great details and arguments why you should not use RAID 5
for a RDBMS implementation
http://www.baarf.com/
GertD@.SQLDev.Net
Please reply only to the newsgroups.
This posting is provided "AS IS" with no warranties, and confers no rights.
You assume all risk for your use.
Copyright © SQLDev.Net 1991-2005 All rights reserved.
"news.microsoft.com" <richk@.bluestreammedia.com> wrote in message
news:OUGbB56EFHA.2176@.TK2MSFTNGP15.phx.gbl...
>I have an external RAID with 10 36GB 15K drives. These drives are only for
> the data of the SQL server, not tran logs, tempdb's etc.
> Database Type is OLTP with more then 30% writes then reads
> This is my question:
> I understand more spindles are better, and I understand RAID 10 is faster
> for writes then a RAID5 configuration. Plus both configurations will give
> me
> enough HD space. So on with the question.
> Should i use RAID 10 or RAID5?
> RAID 10 would give be theoretically faster writes and great protection,
> but
> gives me only 5 disks to write to simultaneously.
> RAID 5 gives me around 9 disks but is known to be slower due to the
> overhead.
> Is the RAID5 really that much slower that it would hinder performance
> compared to a RAID 10 with only 5 disks?
> So what do you guys think?
>
> -King
>sql
the data of the SQL server, not tran logs, tempdb's etc.
Database Type is OLTP with more then 30% writes then reads
This is my question:
I understand more spindles are better, and I understand RAID 10 is faster
for writes then a RAID5 configuration. Plus both configurations will give me
enough HD space. So on with the question.
Should i use RAID 10 or RAID5?
RAID 10 would give be theoretically faster writes and great protection, but
gives me only 5 disks to write to simultaneously.
RAID 5 gives me around 9 disks but is known to be slower due to the
overhead.
Is the RAID5 really that much slower that it would hinder performance
compared to a RAID 10 with only 5 disks?
So what do you guys think?
-Kingyes.
go RAID 1+0
If you have time you can test this with a handful of IOStress test
utilities.
you could also talk directly to your vendor.
As I learned today, you will also want to maximize the WRITE Cache on the
RAID Controller(s).
Cheers
Greg Jackson
PDX, Oregon|||Hi
Where are the transaction logs going? They are as critical to the Db as the
data files.
RAID-10 wins hands down. RAID-5 has just too much overhead for the parity.
From a safety perspective, on RAID-5, you loose 2 drives, bye bye data.
RAID -10 can lose half it's drives, as long as it is never both pairs of a
mirror.
So performance wins.
Regards
--
Mike Epprecht, Microsoft SQL Server MVP
Zurich, Switzerland
IM: mike@.epprecht.net
MVP Program: http://www.microsoft.com/mvp
Blog: http://www.msmvps.com/epprecht/
"news.microsoft.com" <richk@.bluestreammedia.com> wrote in message
news:OUGbB56EFHA.2176@.TK2MSFTNGP15.phx.gbl...
> I have an external RAID with 10 36GB 15K drives. These drives are only
for
> the data of the SQL server, not tran logs, tempdb's etc.
> Database Type is OLTP with more then 30% writes then reads
> This is my question:
> I understand more spindles are better, and I understand RAID 10 is faster
> for writes then a RAID5 configuration. Plus both configurations will give
me
> enough HD space. So on with the question.
> Should i use RAID 10 or RAID5?
> RAID 10 would give be theoretically faster writes and great protection,
but
> gives me only 5 disks to write to simultaneously.
> RAID 5 gives me around 9 disks but is known to be slower due to the
> overhead.
> Is the RAID5 really that much slower that it would hinder performance
> compared to a RAID 10 with only 5 disks?
> So what do you guys think?
>
> -King
>|||Hi
Yes, have write cache, as long as the RAID card has battery backup. If not,
kiss your data goodbye as you will have some decent corruption.
For us, data security over performance, so write caching is off.
Regards
--
Mike Epprecht, Microsoft SQL Server MVP
Zurich, Switzerland
IM: mike@.epprecht.net
MVP Program: http://www.microsoft.com/mvp
Blog: http://www.msmvps.com/epprecht/
"pdxJaxon" <GregoryAJackson@.Hotmail.com> wrote in message
news:#62vk86EFHA.1264@.TK2MSFTNGP12.phx.gbl...
> yes.
> go RAID 1+0
> If you have time you can test this with a handful of IOStress test
> utilities.
> you could also talk directly to your vendor.
> As I learned today, you will also want to maximize the WRITE Cache on the
> RAID Controller(s).
>
> Cheers
> Greg Jackson
> PDX, Oregon
>|||yes....HEAVENS YES.
One needs "battery backed" Cache.
GAJ|||"Mike Epprecht (SQL MVP)" <mike@.epprecht.net> wrote in message
news:%23qs9yC7EFHA.2540@.TK2MSFTNGP09.phx.gbl...
> Hi
> Yes, have write cache, as long as the RAID card has battery backup. If
not,
> kiss your data goodbye as you will have some decent corruption.
>
Yes we have a 72-hour backup on all RAID controllers
> For us, data security over performance, so write caching is off.
> Regards
> --
> Mike Epprecht, Microsoft SQL Server MVP
> Zurich, Switzerland
> IM: mike@.epprecht.net
> MVP Program: http://www.microsoft.com/mvp
> Blog: http://www.msmvps.com/epprecht/
> "pdxJaxon" <GregoryAJackson@.Hotmail.com> wrote in message
> news:#62vk86EFHA.1264@.TK2MSFTNGP12.phx.gbl...
> > yes.
> >
> > go RAID 1+0
> >
> > If you have time you can test this with a handful of IOStress test
> > utilities.
> >
> > you could also talk directly to your vendor.
> >
> > As I learned today, you will also want to maximize the WRITE Cache on
the
> > RAID Controller(s).
> >
> >
> > Cheers
> >
> > Greg Jackson
> > PDX, Oregon
> >
> >
>|||"Mike Epprecht (SQL MVP)" <mike@.epprecht.net> wrote in message
news:e4EdmB7EFHA.4004@.tk2msftngp13.phx.gbl...
> Hi
> Where are the transaction logs going? They are as critical to the Db as
the
> data files.
> RAID-10 wins hands down. RAID-5 has just too much overhead for the parity.
> From a safety perspective, on RAID-5, you loose 2 drives, bye bye data.
> RAID -10 can lose half it's drives, as long as it is never both pairs of a
> mirror.
> So performance wins.
Mike,
Thanks! Thats what i thought.. but what puzzled me was the spindols. Since
the RAID5 configuration would have more drives to spread the write acrossed
then the RAID 1+0 i wasn't sure if it mattered. Keep in mind i haven't got
the hardware yet... so no testing has been done. and yes i will do testing.
thanks for your input.
-King
> Regards
> --
> Mike Epprecht, Microsoft SQL Server MVP
> Zurich, Switzerland
> IM: mike@.epprecht.net
> MVP Program: http://www.microsoft.com/mvp
> Blog: http://www.msmvps.com/epprecht/
> "news.microsoft.com" <richk@.bluestreammedia.com> wrote in message
> news:OUGbB56EFHA.2176@.TK2MSFTNGP15.phx.gbl...
> > I have an external RAID with 10 36GB 15K drives. These drives are only
> for
> > the data of the SQL server, not tran logs, tempdb's etc.
> >
> > Database Type is OLTP with more then 30% writes then reads
> >
> > This is my question:
> >
> > I understand more spindles are better, and I understand RAID 10 is
faster
> > for writes then a RAID5 configuration. Plus both configurations will
give
> me
> > enough HD space. So on with the question.
> >
> > Should i use RAID 10 or RAID5?
> >
> > RAID 10 would give be theoretically faster writes and great protection,
> but
> > gives me only 5 disks to write to simultaneously.
> >
> > RAID 5 gives me around 9 disks but is known to be slower due to the
> > overhead.
> >
> > Is the RAID5 really that much slower that it would hinder performance
> > compared to a RAID 10 with only 5 disks?
> >
> > So what do you guys think?
> >
> >
> > -King
> >
> >
>|||In a Raid 1+0 you can't look at it as only x many drives to write to. In
your case you 10 drives that are configured as such. 5 Mirrored pairs that
are striped in a Raid 0 configuration. Yes that means you have to split the
data 5 ways vs. 9 for the Raid 5 but each split goes to a mirrored pair. The
mirrored pair has the option to read from one disk and write to the other,
write to both, read from both etc. It can be smart in how it reads and
writes to the mirrored pair. That plus the fact it doe not have to
calculate parity is a fast combination.
--
Andrew J. Kelly SQL MVP
"news.microsoft.com" <richk@.bluestreammedia.com> wrote in message
news:%23qHC657EFHA.3672@.TK2MSFTNGP14.phx.gbl...
> "Mike Epprecht (SQL MVP)" <mike@.epprecht.net> wrote in message
> news:e4EdmB7EFHA.4004@.tk2msftngp13.phx.gbl...
>> Hi
>> Where are the transaction logs going? They are as critical to the Db as
> the
>> data files.
>> RAID-10 wins hands down. RAID-5 has just too much overhead for the
>> parity.
>> From a safety perspective, on RAID-5, you loose 2 drives, bye bye data.
>> RAID -10 can lose half it's drives, as long as it is never both pairs of
>> a
>> mirror.
>> So performance wins.
> Mike,
> Thanks! Thats what i thought.. but what puzzled me was the spindols.
> Since
> the RAID5 configuration would have more drives to spread the write
> acrossed
> then the RAID 1+0 i wasn't sure if it mattered. Keep in mind i haven't
> got
> the hardware yet... so no testing has been done. and yes i will do
> testing.
> thanks for your input.
> -King
>
>> Regards
>> --
>> Mike Epprecht, Microsoft SQL Server MVP
>> Zurich, Switzerland
>> IM: mike@.epprecht.net
>> MVP Program: http://www.microsoft.com/mvp
>> Blog: http://www.msmvps.com/epprecht/
>> "news.microsoft.com" <richk@.bluestreammedia.com> wrote in message
>> news:OUGbB56EFHA.2176@.TK2MSFTNGP15.phx.gbl...
>> > I have an external RAID with 10 36GB 15K drives. These drives are only
>> for
>> > the data of the SQL server, not tran logs, tempdb's etc.
>> >
>> > Database Type is OLTP with more then 30% writes then reads
>> >
>> > This is my question:
>> >
>> > I understand more spindles are better, and I understand RAID 10 is
> faster
>> > for writes then a RAID5 configuration. Plus both configurations will
> give
>> me
>> > enough HD space. So on with the question.
>> >
>> > Should i use RAID 10 or RAID5?
>> >
>> > RAID 10 would give be theoretically faster writes and great protection,
>> but
>> > gives me only 5 disks to write to simultaneously.
>> >
>> > RAID 5 gives me around 9 disks but is known to be slower due to the
>> > overhead.
>> >
>> > Is the RAID5 really that much slower that it would hinder performance
>> > compared to a RAID 10 with only 5 disks?
>> >
>> > So what do you guys think?
>> >
>> >
>> > -King
>> >
>> >
>>
>|||This website has great details and arguments why you should not use RAID 5
for a RDBMS implementation
http://www.baarf.com/
GertD@.SQLDev.Net
Please reply only to the newsgroups.
This posting is provided "AS IS" with no warranties, and confers no rights.
You assume all risk for your use.
Copyright © SQLDev.Net 1991-2005 All rights reserved.
"news.microsoft.com" <richk@.bluestreammedia.com> wrote in message
news:OUGbB56EFHA.2176@.TK2MSFTNGP15.phx.gbl...
>I have an external RAID with 10 36GB 15K drives. These drives are only for
> the data of the SQL server, not tran logs, tempdb's etc.
> Database Type is OLTP with more then 30% writes then reads
> This is my question:
> I understand more spindles are better, and I understand RAID 10 is faster
> for writes then a RAID5 configuration. Plus both configurations will give
> me
> enough HD space. So on with the question.
> Should i use RAID 10 or RAID5?
> RAID 10 would give be theoretically faster writes and great protection,
> but
> gives me only 5 disks to write to simultaneously.
> RAID 5 gives me around 9 disks but is known to be slower due to the
> overhead.
> Is the RAID5 really that much slower that it would hinder performance
> compared to a RAID 10 with only 5 disks?
> So what do you guys think?
>
> -King
>sql
RAID 10 Setup Question
Hi Everyone
I really need some clarification on this issue before I start using
this new server.
It has 4 Drives in a RAID 10 config and I need to know if I should
partition then for the following:
Setup 1 - everything on C: Partiton
Setup 2 - 2 Partitions
C: OS
D: SQL DATA / SQL LOGFILES
Setup 3 - 3 Partitions
C: OS
D: SQL DATA
E: SQL LOG FILES
I would have thought there would be more head movement in 2 and 3
partitions but I may be wrong.
IU know SQL does use all the memory which is fine it has 4 gig but
what does everyone recommend i do?
Mattie
Using logical partitions on the same physical drive array do nothing for
performance but can give the illusion as such to people who may not know
that physical layout. If there is no choice but to have a single drive array
I prefer to have only 1 partition. That way there is never a problem if you
made one too large or too small later down the road.
Andrew J. Kelly SQL MVP
"MattieG" <mattiegriffin@.hotmail.co.uk> wrote in message
news:1183731888.891067.55660@.g13g2000hsf.googlegro ups.com...
> Hi Everyone
> I really need some clarification on this issue before I start using
> this new server.
> It has 4 Drives in a RAID 10 config and I need to know if I should
> partition then for the following:
> Setup 1 - everything on C: Partiton
> Setup 2 - 2 Partitions
> C: OS
> D: SQL DATA / SQL LOGFILES
> Setup 3 - 3 Partitions
> C: OS
> D: SQL DATA
> E: SQL LOG FILES
> I would have thought there would be more head movement in 2 and 3
> partitions but I may be wrong.
> IU know SQL does use all the memory which is fine it has 4 gig but
> what does everyone recommend i do?
> Mattie
>
|||MattieG,
I definitely understand Andrew's contention that unpartitioned is less
deceptive. (And partitioning caused me some serious grief once.)
Do you think you will get leverage to eventually separate the disks so that
you have log files on a different physical array? If so, then partitioning
now will allow your file paths to be set up for the future arrival of real
disks. But, if you do not do it now, it is not difficult to move files in
that happy future day.
RLF
"MattieG" <mattiegriffin@.hotmail.co.uk> wrote in message
news:1183731888.891067.55660@.g13g2000hsf.googlegro ups.com...
> Hi Everyone
> I really need some clarification on this issue before I start using
> this new server.
> It has 4 Drives in a RAID 10 config and I need to know if I should
> partition then for the following:
> Setup 1 - everything on C: Partiton
> Setup 2 - 2 Partitions
> C: OS
> D: SQL DATA / SQL LOGFILES
> Setup 3 - 3 Partitions
> C: OS
> D: SQL DATA
> E: SQL LOG FILES
> I would have thought there would be more head movement in 2 and 3
> partitions but I may be wrong.
> IU know SQL does use all the memory which is fine it has 4 gig but
> what does everyone recommend i do?
> Mattie
>
|||Cool, that confirmed my suspicions
Im actually looking at getting a couple more disks for the OS or
possibly OS+Database
and maybe use the raid 10 for the log files only.
Unless I use 3 raid 1 arrays for OS / Database / Logfile?
Mattie
|||I don't know how busy this will be but if you get two more disks and create
a Raid 1 I would put the OS and possibly the log files (both user and
tempdb) on that array. Then leave the data files on the Raid 10. The OS
doesn't get used much and at least you would separate the data and log
files.
Andrew J. Kelly SQL MVP
"MattieG" <mattiegriffin@.hotmail.co.uk> wrote in message
news:1183737319.730417.129770@.c77g2000hse.googlegr oups.com...
> Cool, that confirmed my suspicions
> Im actually looking at getting a couple more disks for the OS or
> possibly OS+Database
> and maybe use the raid 10 for the log files only.
> Unless I use 3 raid 1 arrays for OS / Database / Logfile?
> Mattie
>
|||Here is an article I wrote on setting up disk configurations.
http://searchsqlserver.techtarget.com/tip/0,289483,sid87_gci1262122,00.html
Denny
MCSA (2003) / MCDBA (SQL 2000)
MCTS (SQL 2005 / Microsoft Windows SharePoint Services 3.0: Configuration /
Microsoft Office SharePoint Server 2007: Configuration)
MCITP (dbadmin, dbdev)
"MattieG" wrote:
> Hi Everyone
> I really need some clarification on this issue before I start using
> this new server.
> It has 4 Drives in a RAID 10 config and I need to know if I should
> partition then for the following:
> Setup 1 - everything on C: Partiton
> Setup 2 - 2 Partitions
> C: OS
> D: SQL DATA / SQL LOGFILES
> Setup 3 - 3 Partitions
> C: OS
> D: SQL DATA
> E: SQL LOG FILES
> I would have thought there would be more head movement in 2 and 3
> partitions but I may be wrong.
> IU know SQL does use all the memory which is fine it has 4 gig but
> what does everyone recommend i do?
> Mattie
>
|||?Hi
Thanks for everything I will order some more disks.
Mattie
|||I will add one comment to Andrew's suggestion. Consider a 4 disk raid 5 set
for your data files if the databases are more select oriented than heavy
insert/update/delete oriented. The 4 disk raid 5 will get you 3 active
spindles for reads which will offer 50% better read throughput than a 4 disk
raid 10 set which has only 2 active spindles serving data. At least I THINK
it works that way. ;)
TheSQLGuru
President
Indicium Resources, Inc.
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
news:O7NP4Q$vHHA.3400@.TK2MSFTNGP03.phx.gbl...
>I don't know how busy this will be but if you get two more disks and create
>a Raid 1 I would put the OS and possibly the log files (both user and
>tempdb) on that array. Then leave the data files on the Raid 10. The OS
>doesn't get used much and at least you would separate the data and log
>files.
> --
> Andrew J. Kelly SQL MVP
> "MattieG" <mattiegriffin@.hotmail.co.uk> wrote in message
> news:1183737319.730417.129770@.c77g2000hse.googlegr oups.com...
>
|||>The 4 disk raid 5 will get you 3 active spindles for reads which will offer
>50% better read throughput than a 4 disk raid 10 set which has only 2
>active spindles serving data.
Not quite. While a 4 disk RAID 5 may outperform a 4 disk Raid 10 for
strictly read operations of large scale it will not be anywhere close to 50%
in my experience. And don't forget that a smart Raid controller can access
both disks in the mirrored pair at the same time for different operations.
Andrew J. Kelly SQL MVP
"TheSQLGuru" <kgboles@.earthlink.net> wrote in message
news:eeDOTMkwHHA.600@.TK2MSFTNGP05.phx.gbl...
>I will add one comment to Andrew's suggestion. Consider a 4 disk raid 5
>set for your data files if the databases are more select oriented than
>heavy insert/update/delete oriented. The 4 disk raid 5 will get you 3
>active spindles for reads which will offer 50% better read throughput than
>a 4 disk raid 10 set which has only 2 active spindles serving data. At
>least I THINK it works that way. ;)
> --
> TheSQLGuru
> President
> Indicium Resources, Inc.
> "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
> news:O7NP4Q$vHHA.3400@.TK2MSFTNGP03.phx.gbl...
>
|||>>And don't forget that a smart Raid controller can access both disks in[vbcol=seagreen]
That was the part I wasn't sure about. I didn't know if the controller
would be able to maintain data integrity if it flipped back and forth
between the drives accessing different areas for different read/write
operations.
TheSQLGuru
President
Indicium Resources, Inc.
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
news:uapeltnwHHA.4800@.TK2MSFTNGP05.phx.gbl...
> Not quite. While a 4 disk RAID 5 may outperform a 4 disk Raid 10 for
> strictly read operations of large scale it will not be anywhere close to
> 50% in my experience. And don't forget that a smart Raid controller can
> access both disks in the mirrored pair at the same time for different
> operations.
> --
> Andrew J. Kelly SQL MVP
> "TheSQLGuru" <kgboles@.earthlink.net> wrote in message
> news:eeDOTMkwHHA.600@.TK2MSFTNGP05.phx.gbl...
>
I really need some clarification on this issue before I start using
this new server.
It has 4 Drives in a RAID 10 config and I need to know if I should
partition then for the following:
Setup 1 - everything on C: Partiton
Setup 2 - 2 Partitions
C: OS
D: SQL DATA / SQL LOGFILES
Setup 3 - 3 Partitions
C: OS
D: SQL DATA
E: SQL LOG FILES
I would have thought there would be more head movement in 2 and 3
partitions but I may be wrong.
IU know SQL does use all the memory which is fine it has 4 gig but
what does everyone recommend i do?
Mattie
Using logical partitions on the same physical drive array do nothing for
performance but can give the illusion as such to people who may not know
that physical layout. If there is no choice but to have a single drive array
I prefer to have only 1 partition. That way there is never a problem if you
made one too large or too small later down the road.
Andrew J. Kelly SQL MVP
"MattieG" <mattiegriffin@.hotmail.co.uk> wrote in message
news:1183731888.891067.55660@.g13g2000hsf.googlegro ups.com...
> Hi Everyone
> I really need some clarification on this issue before I start using
> this new server.
> It has 4 Drives in a RAID 10 config and I need to know if I should
> partition then for the following:
> Setup 1 - everything on C: Partiton
> Setup 2 - 2 Partitions
> C: OS
> D: SQL DATA / SQL LOGFILES
> Setup 3 - 3 Partitions
> C: OS
> D: SQL DATA
> E: SQL LOG FILES
> I would have thought there would be more head movement in 2 and 3
> partitions but I may be wrong.
> IU know SQL does use all the memory which is fine it has 4 gig but
> what does everyone recommend i do?
> Mattie
>
|||MattieG,
I definitely understand Andrew's contention that unpartitioned is less
deceptive. (And partitioning caused me some serious grief once.)
Do you think you will get leverage to eventually separate the disks so that
you have log files on a different physical array? If so, then partitioning
now will allow your file paths to be set up for the future arrival of real
disks. But, if you do not do it now, it is not difficult to move files in
that happy future day.
RLF
"MattieG" <mattiegriffin@.hotmail.co.uk> wrote in message
news:1183731888.891067.55660@.g13g2000hsf.googlegro ups.com...
> Hi Everyone
> I really need some clarification on this issue before I start using
> this new server.
> It has 4 Drives in a RAID 10 config and I need to know if I should
> partition then for the following:
> Setup 1 - everything on C: Partiton
> Setup 2 - 2 Partitions
> C: OS
> D: SQL DATA / SQL LOGFILES
> Setup 3 - 3 Partitions
> C: OS
> D: SQL DATA
> E: SQL LOG FILES
> I would have thought there would be more head movement in 2 and 3
> partitions but I may be wrong.
> IU know SQL does use all the memory which is fine it has 4 gig but
> what does everyone recommend i do?
> Mattie
>
|||Cool, that confirmed my suspicions
Im actually looking at getting a couple more disks for the OS or
possibly OS+Database
and maybe use the raid 10 for the log files only.
Unless I use 3 raid 1 arrays for OS / Database / Logfile?
Mattie
|||I don't know how busy this will be but if you get two more disks and create
a Raid 1 I would put the OS and possibly the log files (both user and
tempdb) on that array. Then leave the data files on the Raid 10. The OS
doesn't get used much and at least you would separate the data and log
files.
Andrew J. Kelly SQL MVP
"MattieG" <mattiegriffin@.hotmail.co.uk> wrote in message
news:1183737319.730417.129770@.c77g2000hse.googlegr oups.com...
> Cool, that confirmed my suspicions
> Im actually looking at getting a couple more disks for the OS or
> possibly OS+Database
> and maybe use the raid 10 for the log files only.
> Unless I use 3 raid 1 arrays for OS / Database / Logfile?
> Mattie
>
|||Here is an article I wrote on setting up disk configurations.
http://searchsqlserver.techtarget.com/tip/0,289483,sid87_gci1262122,00.html
Denny
MCSA (2003) / MCDBA (SQL 2000)
MCTS (SQL 2005 / Microsoft Windows SharePoint Services 3.0: Configuration /
Microsoft Office SharePoint Server 2007: Configuration)
MCITP (dbadmin, dbdev)
"MattieG" wrote:
> Hi Everyone
> I really need some clarification on this issue before I start using
> this new server.
> It has 4 Drives in a RAID 10 config and I need to know if I should
> partition then for the following:
> Setup 1 - everything on C: Partiton
> Setup 2 - 2 Partitions
> C: OS
> D: SQL DATA / SQL LOGFILES
> Setup 3 - 3 Partitions
> C: OS
> D: SQL DATA
> E: SQL LOG FILES
> I would have thought there would be more head movement in 2 and 3
> partitions but I may be wrong.
> IU know SQL does use all the memory which is fine it has 4 gig but
> what does everyone recommend i do?
> Mattie
>
|||?Hi
Thanks for everything
I will order some more disks.Mattie
|||I will add one comment to Andrew's suggestion. Consider a 4 disk raid 5 set
for your data files if the databases are more select oriented than heavy
insert/update/delete oriented. The 4 disk raid 5 will get you 3 active
spindles for reads which will offer 50% better read throughput than a 4 disk
raid 10 set which has only 2 active spindles serving data. At least I THINK
it works that way. ;)
TheSQLGuru
President
Indicium Resources, Inc.
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
news:O7NP4Q$vHHA.3400@.TK2MSFTNGP03.phx.gbl...
>I don't know how busy this will be but if you get two more disks and create
>a Raid 1 I would put the OS and possibly the log files (both user and
>tempdb) on that array. Then leave the data files on the Raid 10. The OS
>doesn't get used much and at least you would separate the data and log
>files.
> --
> Andrew J. Kelly SQL MVP
> "MattieG" <mattiegriffin@.hotmail.co.uk> wrote in message
> news:1183737319.730417.129770@.c77g2000hse.googlegr oups.com...
>
|||>The 4 disk raid 5 will get you 3 active spindles for reads which will offer
>50% better read throughput than a 4 disk raid 10 set which has only 2
>active spindles serving data.
Not quite. While a 4 disk RAID 5 may outperform a 4 disk Raid 10 for
strictly read operations of large scale it will not be anywhere close to 50%
in my experience. And don't forget that a smart Raid controller can access
both disks in the mirrored pair at the same time for different operations.
Andrew J. Kelly SQL MVP
"TheSQLGuru" <kgboles@.earthlink.net> wrote in message
news:eeDOTMkwHHA.600@.TK2MSFTNGP05.phx.gbl...
>I will add one comment to Andrew's suggestion. Consider a 4 disk raid 5
>set for your data files if the databases are more select oriented than
>heavy insert/update/delete oriented. The 4 disk raid 5 will get you 3
>active spindles for reads which will offer 50% better read throughput than
>a 4 disk raid 10 set which has only 2 active spindles serving data. At
>least I THINK it works that way. ;)
> --
> TheSQLGuru
> President
> Indicium Resources, Inc.
> "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
> news:O7NP4Q$vHHA.3400@.TK2MSFTNGP03.phx.gbl...
>
|||>>And don't forget that a smart Raid controller can access both disks in[vbcol=seagreen]
That was the part I wasn't sure about. I didn't know if the controller
would be able to maintain data integrity if it flipped back and forth
between the drives accessing different areas for different read/write
operations.
TheSQLGuru
President
Indicium Resources, Inc.
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
news:uapeltnwHHA.4800@.TK2MSFTNGP05.phx.gbl...
> Not quite. While a 4 disk RAID 5 may outperform a 4 disk Raid 10 for
> strictly read operations of large scale it will not be anywhere close to
> 50% in my experience. And don't forget that a smart Raid controller can
> access both disks in the mirrored pair at the same time for different
> operations.
> --
> Andrew J. Kelly SQL MVP
> "TheSQLGuru" <kgboles@.earthlink.net> wrote in message
> news:eeDOTMkwHHA.600@.TK2MSFTNGP05.phx.gbl...
>
Monday, March 26, 2012
RAID 10 Setup Question
Hi Everyone
I really need some clarification on this issue before I start using
this new server.
It has 4 Drives in a RAID 10 config and I need to know if I should
partition then for the following:
Setup 1 - everything on C: Partiton
Setup 2 - 2 Partitions
C: OS
D: SQL DATA / SQL LOGFILES
Setup 3 - 3 Partitions
C: OS
D: SQL DATA
E: SQL LOG FILES
I would have thought there would be more head movement in 2 and 3
partitions but I may be wrong.
IU know SQL does use all the memory which is fine it has 4 gig but
what does everyone recommend i do?
MattieUsing logical partitions on the same physical drive array do nothing for
performance but can give the illusion as such to people who may not know
that physical layout. If there is no choice but to have a single drive array
I prefer to have only 1 partition. That way there is never a problem if you
made one too large or too small later down the road.
--
Andrew J. Kelly SQL MVP
"MattieG" <mattiegriffin@.hotmail.co.uk> wrote in message
news:1183731888.891067.55660@.g13g2000hsf.googlegroups.com...
> Hi Everyone
> I really need some clarification on this issue before I start using
> this new server.
> It has 4 Drives in a RAID 10 config and I need to know if I should
> partition then for the following:
> Setup 1 - everything on C: Partiton
> Setup 2 - 2 Partitions
> C: OS
> D: SQL DATA / SQL LOGFILES
> Setup 3 - 3 Partitions
> C: OS
> D: SQL DATA
> E: SQL LOG FILES
> I would have thought there would be more head movement in 2 and 3
> partitions but I may be wrong.
> IU know SQL does use all the memory which is fine it has 4 gig but
> what does everyone recommend i do?
> Mattie
>|||MattieG,
I definitely understand Andrew's contention that unpartitioned is less
deceptive. (And partitioning caused me some serious grief once.)
Do you think you will get leverage to eventually separate the disks so that
you have log files on a different physical array? If so, then partitioning
now will allow your file paths to be set up for the future arrival of real
disks. But, if you do not do it now, it is not difficult to move files in
that happy future day.
RLF
"MattieG" <mattiegriffin@.hotmail.co.uk> wrote in message
news:1183731888.891067.55660@.g13g2000hsf.googlegroups.com...
> Hi Everyone
> I really need some clarification on this issue before I start using
> this new server.
> It has 4 Drives in a RAID 10 config and I need to know if I should
> partition then for the following:
> Setup 1 - everything on C: Partiton
> Setup 2 - 2 Partitions
> C: OS
> D: SQL DATA / SQL LOGFILES
> Setup 3 - 3 Partitions
> C: OS
> D: SQL DATA
> E: SQL LOG FILES
> I would have thought there would be more head movement in 2 and 3
> partitions but I may be wrong.
> IU know SQL does use all the memory which is fine it has 4 gig but
> what does everyone recommend i do?
> Mattie
>|||Cool, that confirmed my suspicions :)
Im actually looking at getting a couple more disks for the OS or
possibly OS+Database
and maybe use the raid 10 for the log files only.
Unless I use 3 raid 1 arrays for OS / Database / Logfile?
Mattie|||I don't know how busy this will be but if you get two more disks and create
a Raid 1 I would put the OS and possibly the log files (both user and
tempdb) on that array. Then leave the data files on the Raid 10. The OS
doesn't get used much and at least you would separate the data and log
files.
--
Andrew J. Kelly SQL MVP
"MattieG" <mattiegriffin@.hotmail.co.uk> wrote in message
news:1183737319.730417.129770@.c77g2000hse.googlegroups.com...
> Cool, that confirmed my suspicions :)
> Im actually looking at getting a couple more disks for the OS or
> possibly OS+Database
> and maybe use the raid 10 for the log files only.
> Unless I use 3 raid 1 arrays for OS / Database / Logfile?
> Mattie
>|||Here is an article I wrote on setting up disk configurations.
http://searchsqlserver.techtarget.com/tip/0,289483,sid87_gci1262122,00.html
--
Denny
MCSA (2003) / MCDBA (SQL 2000)
MCTS (SQL 2005 / Microsoft Windows SharePoint Services 3.0: Configuration /
Microsoft Office SharePoint Server 2007: Configuration)
MCITP (dbadmin, dbdev)
"MattieG" wrote:
> Hi Everyone
> I really need some clarification on this issue before I start using
> this new server.
> It has 4 Drives in a RAID 10 config and I need to know if I should
> partition then for the following:
> Setup 1 - everything on C: Partiton
> Setup 2 - 2 Partitions
> C: OS
> D: SQL DATA / SQL LOGFILES
> Setup 3 - 3 Partitions
> C: OS
> D: SQL DATA
> E: SQL LOG FILES
> I would have thought there would be more head movement in 2 and 3
> partitions but I may be wrong.
> IU know SQL does use all the memory which is fine it has 4 gig but
> what does everyone recommend i do?
> Mattie
>|||?Hi
Thanks for everything :) I will order some more disks.
Mattie|||I will add one comment to Andrew's suggestion. Consider a 4 disk raid 5 set
for your data files if the databases are more select oriented than heavy
insert/update/delete oriented. The 4 disk raid 5 will get you 3 active
spindles for reads which will offer 50% better read throughput than a 4 disk
raid 10 set which has only 2 active spindles serving data. At least I THINK
it works that way. ;)
--
TheSQLGuru
President
Indicium Resources, Inc.
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
news:O7NP4Q$vHHA.3400@.TK2MSFTNGP03.phx.gbl...
>I don't know how busy this will be but if you get two more disks and create
>a Raid 1 I would put the OS and possibly the log files (both user and
>tempdb) on that array. Then leave the data files on the Raid 10. The OS
>doesn't get used much and at least you would separate the data and log
>files.
> --
> Andrew J. Kelly SQL MVP
> "MattieG" <mattiegriffin@.hotmail.co.uk> wrote in message
> news:1183737319.730417.129770@.c77g2000hse.googlegroups.com...
>> Cool, that confirmed my suspicions :)
>> Im actually looking at getting a couple more disks for the OS or
>> possibly OS+Database
>> and maybe use the raid 10 for the log files only.
>> Unless I use 3 raid 1 arrays for OS / Database / Logfile?
>> Mattie
>>
>|||>The 4 disk raid 5 will get you 3 active spindles for reads which will offer
>50% better read throughput than a 4 disk raid 10 set which has only 2
>active spindles serving data.
Not quite. While a 4 disk RAID 5 may outperform a 4 disk Raid 10 for
strictly read operations of large scale it will not be anywhere close to 50%
in my experience. And don't forget that a smart Raid controller can access
both disks in the mirrored pair at the same time for different operations.
--
Andrew J. Kelly SQL MVP
"TheSQLGuru" <kgboles@.earthlink.net> wrote in message
news:eeDOTMkwHHA.600@.TK2MSFTNGP05.phx.gbl...
>I will add one comment to Andrew's suggestion. Consider a 4 disk raid 5
>set for your data files if the databases are more select oriented than
>heavy insert/update/delete oriented. The 4 disk raid 5 will get you 3
>active spindles for reads which will offer 50% better read throughput than
>a 4 disk raid 10 set which has only 2 active spindles serving data. At
>least I THINK it works that way. ;)
> --
> TheSQLGuru
> President
> Indicium Resources, Inc.
> "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
> news:O7NP4Q$vHHA.3400@.TK2MSFTNGP03.phx.gbl...
>>I don't know how busy this will be but if you get two more disks and
>>create a Raid 1 I would put the OS and possibly the log files (both user
>>and tempdb) on that array. Then leave the data files on the Raid 10. The
>>OS doesn't get used much and at least you would separate the data and log
>>files.
>> --
>> Andrew J. Kelly SQL MVP
>> "MattieG" <mattiegriffin@.hotmail.co.uk> wrote in message
>> news:1183737319.730417.129770@.c77g2000hse.googlegroups.com...
>> Cool, that confirmed my suspicions :)
>> Im actually looking at getting a couple more disks for the OS or
>> possibly OS+Database
>> and maybe use the raid 10 for the log files only.
>> Unless I use 3 raid 1 arrays for OS / Database / Logfile?
>> Mattie
>>
>>
>|||>>And don't forget that a smart Raid controller can access both disks in
>>the mirrored pair at the same time for different operations.
That was the part I wasn't sure about. I didn't know if the controller
would be able to maintain data integrity if it flipped back and forth
between the drives accessing different areas for different read/write
operations.
TheSQLGuru
President
Indicium Resources, Inc.
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
news:uapeltnwHHA.4800@.TK2MSFTNGP05.phx.gbl...
> >The 4 disk raid 5 will get you 3 active spindles for reads which will
> >offer 50% better read throughput than a 4 disk raid 10 set which has only
> >2 active spindles serving data.
> Not quite. While a 4 disk RAID 5 may outperform a 4 disk Raid 10 for
> strictly read operations of large scale it will not be anywhere close to
> 50% in my experience. And don't forget that a smart Raid controller can
> access both disks in the mirrored pair at the same time for different
> operations.
> --
> Andrew J. Kelly SQL MVP
> "TheSQLGuru" <kgboles@.earthlink.net> wrote in message
> news:eeDOTMkwHHA.600@.TK2MSFTNGP05.phx.gbl...
>>I will add one comment to Andrew's suggestion. Consider a 4 disk raid 5
>>set for your data files if the databases are more select oriented than
>>heavy insert/update/delete oriented. The 4 disk raid 5 will get you 3
>>active spindles for reads which will offer 50% better read throughput than
>>a 4 disk raid 10 set which has only 2 active spindles serving data. At
>>least I THINK it works that way. ;)
>> --
>> TheSQLGuru
>> President
>> Indicium Resources, Inc.
>> "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
>> news:O7NP4Q$vHHA.3400@.TK2MSFTNGP03.phx.gbl...
>>I don't know how busy this will be but if you get two more disks and
>>create a Raid 1 I would put the OS and possibly the log files (both user
>>and tempdb) on that array. Then leave the data files on the Raid 10. The
>>OS doesn't get used much and at least you would separate the data and log
>>files.
>> --
>> Andrew J. Kelly SQL MVP
>> "MattieG" <mattiegriffin@.hotmail.co.uk> wrote in message
>> news:1183737319.730417.129770@.c77g2000hse.googlegroups.com...
>> Cool, that confirmed my suspicions :)
>> Im actually looking at getting a couple more disks for the OS or
>> possibly OS+Database
>> and maybe use the raid 10 for the log files only.
>> Unless I use 3 raid 1 arrays for OS / Database / Logfile?
>> Mattie
>>
>>
>>
>|||don't think that raid controler is permitted to perform different tasks on
mirrored disks.
smart [very smart & very expensive] raid controler may perform doubled read
from raid1 array, reading at the same time sector_x from disk_0, and
sector_y from disk_1, so having read two sectors at the time tick of just
one.
for this reason raid controler should have very good knowledge of current
head/track location of each disks, and to manage them separately.
information i found just show that this is rarely a case, mostly raid
controler uses just one of raid1 disks for reading, usualy one having better
response time.
the best thing i found useful is using *outer* cylindres for best
performances. on new disks, 25% of outer cylindres has a 25% better
throughoutput then the rest of disk. so, i made on each disk two partitions,
outer, for quick files transfer/read, and inner, for some backup [to not
waste space].
my sql database is only 20gig,, so the smaller outer partition on larger
disks is quite enough.
for tempdb, which needs quick read/write, but not to survive shutdown, maybe
to use i-ram [it is pc card with 4gb ram, connected to mb as ordinarly sata
drive] since it is very fast, but limited to 4gb, possible to form jbod
disk, i-ram and one regular hd, so to allow tempdb, if overgow the 4gb space
to take place on larger second drive.
just my few observations ...
"TheSQLGuru" <kgboles@.earthlink.net> wrote in message
news:uBYpnj8wHHA.3796@.TK2MSFTNGP04.phx.gbl...
> >>And don't forget that a smart Raid controller can access both disks in
> >>the mirrored pair at the same time for different operations.
> That was the part I wasn't sure about. I didn't know if the controller
> would be able to maintain data integrity if it flipped back and forth
> between the drives accessing different areas for different read/write
> operations.
>|||I haven't gone to that level recently but I remember years ago the DPT raid
controllers used to be able to read from one disk and write to the other at
the same time. It would then do the necessary deferred writes to keep them
in sync of coarse. As long as the cache and types of activities were
compatible it seemed to work just fine. So I assume with more modern
technology this is still true but I can't confirm that for sure.
--
Andrew J. Kelly SQL MVP
"sali" <gabor.salai@.tel.net.ba> wrote in message
news:%236csKJ$wHHA.1208@.TK2MSFTNGP03.phx.gbl...
> don't think that raid controler is permitted to perform different tasks on
> mirrored disks.
> smart [very smart & very expensive] raid controler may perform doubled
> read
> from raid1 array, reading at the same time sector_x from disk_0, and
> sector_y from disk_1, so having read two sectors at the time tick of just
> one.
> for this reason raid controler should have very good knowledge of current
> head/track location of each disks, and to manage them separately.
> information i found just show that this is rarely a case, mostly raid
> controler uses just one of raid1 disks for reading, usualy one having
> better
> response time.
> the best thing i found useful is using *outer* cylindres for best
> performances. on new disks, 25% of outer cylindres has a 25% better
> throughoutput then the rest of disk. so, i made on each disk two
> partitions,
> outer, for quick files transfer/read, and inner, for some backup [to not
> waste space].
> my sql database is only 20gig,, so the smaller outer partition on larger
> disks is quite enough.
> for tempdb, which needs quick read/write, but not to survive shutdown,
> maybe
> to use i-ram [it is pc card with 4gb ram, connected to mb as ordinarly
> sata
> drive] since it is very fast, but limited to 4gb, possible to form jbod
> disk, i-ram and one regular hd, so to allow tempdb, if overgow the 4gb
> space
> to take place on larger second drive.
> just my few observations ...
>
> "TheSQLGuru" <kgboles@.earthlink.net> wrote in message
> news:uBYpnj8wHHA.3796@.TK2MSFTNGP04.phx.gbl...
>> >>And don't forget that a smart Raid controller can access both disks in
>> >>the mirrored pair at the same time for different operations.
>> That was the part I wasn't sure about. I didn't know if the controller
>> would be able to maintain data integrity if it flipped back and forth
>> between the drives accessing different areas for different read/write
>> operations.
>
>
I really need some clarification on this issue before I start using
this new server.
It has 4 Drives in a RAID 10 config and I need to know if I should
partition then for the following:
Setup 1 - everything on C: Partiton
Setup 2 - 2 Partitions
C: OS
D: SQL DATA / SQL LOGFILES
Setup 3 - 3 Partitions
C: OS
D: SQL DATA
E: SQL LOG FILES
I would have thought there would be more head movement in 2 and 3
partitions but I may be wrong.
IU know SQL does use all the memory which is fine it has 4 gig but
what does everyone recommend i do?
MattieUsing logical partitions on the same physical drive array do nothing for
performance but can give the illusion as such to people who may not know
that physical layout. If there is no choice but to have a single drive array
I prefer to have only 1 partition. That way there is never a problem if you
made one too large or too small later down the road.
--
Andrew J. Kelly SQL MVP
"MattieG" <mattiegriffin@.hotmail.co.uk> wrote in message
news:1183731888.891067.55660@.g13g2000hsf.googlegroups.com...
> Hi Everyone
> I really need some clarification on this issue before I start using
> this new server.
> It has 4 Drives in a RAID 10 config and I need to know if I should
> partition then for the following:
> Setup 1 - everything on C: Partiton
> Setup 2 - 2 Partitions
> C: OS
> D: SQL DATA / SQL LOGFILES
> Setup 3 - 3 Partitions
> C: OS
> D: SQL DATA
> E: SQL LOG FILES
> I would have thought there would be more head movement in 2 and 3
> partitions but I may be wrong.
> IU know SQL does use all the memory which is fine it has 4 gig but
> what does everyone recommend i do?
> Mattie
>|||MattieG,
I definitely understand Andrew's contention that unpartitioned is less
deceptive. (And partitioning caused me some serious grief once.)
Do you think you will get leverage to eventually separate the disks so that
you have log files on a different physical array? If so, then partitioning
now will allow your file paths to be set up for the future arrival of real
disks. But, if you do not do it now, it is not difficult to move files in
that happy future day.
RLF
"MattieG" <mattiegriffin@.hotmail.co.uk> wrote in message
news:1183731888.891067.55660@.g13g2000hsf.googlegroups.com...
> Hi Everyone
> I really need some clarification on this issue before I start using
> this new server.
> It has 4 Drives in a RAID 10 config and I need to know if I should
> partition then for the following:
> Setup 1 - everything on C: Partiton
> Setup 2 - 2 Partitions
> C: OS
> D: SQL DATA / SQL LOGFILES
> Setup 3 - 3 Partitions
> C: OS
> D: SQL DATA
> E: SQL LOG FILES
> I would have thought there would be more head movement in 2 and 3
> partitions but I may be wrong.
> IU know SQL does use all the memory which is fine it has 4 gig but
> what does everyone recommend i do?
> Mattie
>|||Cool, that confirmed my suspicions :)
Im actually looking at getting a couple more disks for the OS or
possibly OS+Database
and maybe use the raid 10 for the log files only.
Unless I use 3 raid 1 arrays for OS / Database / Logfile?
Mattie|||I don't know how busy this will be but if you get two more disks and create
a Raid 1 I would put the OS and possibly the log files (both user and
tempdb) on that array. Then leave the data files on the Raid 10. The OS
doesn't get used much and at least you would separate the data and log
files.
--
Andrew J. Kelly SQL MVP
"MattieG" <mattiegriffin@.hotmail.co.uk> wrote in message
news:1183737319.730417.129770@.c77g2000hse.googlegroups.com...
> Cool, that confirmed my suspicions :)
> Im actually looking at getting a couple more disks for the OS or
> possibly OS+Database
> and maybe use the raid 10 for the log files only.
> Unless I use 3 raid 1 arrays for OS / Database / Logfile?
> Mattie
>|||Here is an article I wrote on setting up disk configurations.
http://searchsqlserver.techtarget.com/tip/0,289483,sid87_gci1262122,00.html
--
Denny
MCSA (2003) / MCDBA (SQL 2000)
MCTS (SQL 2005 / Microsoft Windows SharePoint Services 3.0: Configuration /
Microsoft Office SharePoint Server 2007: Configuration)
MCITP (dbadmin, dbdev)
"MattieG" wrote:
> Hi Everyone
> I really need some clarification on this issue before I start using
> this new server.
> It has 4 Drives in a RAID 10 config and I need to know if I should
> partition then for the following:
> Setup 1 - everything on C: Partiton
> Setup 2 - 2 Partitions
> C: OS
> D: SQL DATA / SQL LOGFILES
> Setup 3 - 3 Partitions
> C: OS
> D: SQL DATA
> E: SQL LOG FILES
> I would have thought there would be more head movement in 2 and 3
> partitions but I may be wrong.
> IU know SQL does use all the memory which is fine it has 4 gig but
> what does everyone recommend i do?
> Mattie
>|||?Hi
Thanks for everything :) I will order some more disks.
Mattie|||I will add one comment to Andrew's suggestion. Consider a 4 disk raid 5 set
for your data files if the databases are more select oriented than heavy
insert/update/delete oriented. The 4 disk raid 5 will get you 3 active
spindles for reads which will offer 50% better read throughput than a 4 disk
raid 10 set which has only 2 active spindles serving data. At least I THINK
it works that way. ;)
--
TheSQLGuru
President
Indicium Resources, Inc.
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
news:O7NP4Q$vHHA.3400@.TK2MSFTNGP03.phx.gbl...
>I don't know how busy this will be but if you get two more disks and create
>a Raid 1 I would put the OS and possibly the log files (both user and
>tempdb) on that array. Then leave the data files on the Raid 10. The OS
>doesn't get used much and at least you would separate the data and log
>files.
> --
> Andrew J. Kelly SQL MVP
> "MattieG" <mattiegriffin@.hotmail.co.uk> wrote in message
> news:1183737319.730417.129770@.c77g2000hse.googlegroups.com...
>> Cool, that confirmed my suspicions :)
>> Im actually looking at getting a couple more disks for the OS or
>> possibly OS+Database
>> and maybe use the raid 10 for the log files only.
>> Unless I use 3 raid 1 arrays for OS / Database / Logfile?
>> Mattie
>>
>|||>The 4 disk raid 5 will get you 3 active spindles for reads which will offer
>50% better read throughput than a 4 disk raid 10 set which has only 2
>active spindles serving data.
Not quite. While a 4 disk RAID 5 may outperform a 4 disk Raid 10 for
strictly read operations of large scale it will not be anywhere close to 50%
in my experience. And don't forget that a smart Raid controller can access
both disks in the mirrored pair at the same time for different operations.
--
Andrew J. Kelly SQL MVP
"TheSQLGuru" <kgboles@.earthlink.net> wrote in message
news:eeDOTMkwHHA.600@.TK2MSFTNGP05.phx.gbl...
>I will add one comment to Andrew's suggestion. Consider a 4 disk raid 5
>set for your data files if the databases are more select oriented than
>heavy insert/update/delete oriented. The 4 disk raid 5 will get you 3
>active spindles for reads which will offer 50% better read throughput than
>a 4 disk raid 10 set which has only 2 active spindles serving data. At
>least I THINK it works that way. ;)
> --
> TheSQLGuru
> President
> Indicium Resources, Inc.
> "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
> news:O7NP4Q$vHHA.3400@.TK2MSFTNGP03.phx.gbl...
>>I don't know how busy this will be but if you get two more disks and
>>create a Raid 1 I would put the OS and possibly the log files (both user
>>and tempdb) on that array. Then leave the data files on the Raid 10. The
>>OS doesn't get used much and at least you would separate the data and log
>>files.
>> --
>> Andrew J. Kelly SQL MVP
>> "MattieG" <mattiegriffin@.hotmail.co.uk> wrote in message
>> news:1183737319.730417.129770@.c77g2000hse.googlegroups.com...
>> Cool, that confirmed my suspicions :)
>> Im actually looking at getting a couple more disks for the OS or
>> possibly OS+Database
>> and maybe use the raid 10 for the log files only.
>> Unless I use 3 raid 1 arrays for OS / Database / Logfile?
>> Mattie
>>
>>
>|||>>And don't forget that a smart Raid controller can access both disks in
>>the mirrored pair at the same time for different operations.
That was the part I wasn't sure about. I didn't know if the controller
would be able to maintain data integrity if it flipped back and forth
between the drives accessing different areas for different read/write
operations.
TheSQLGuru
President
Indicium Resources, Inc.
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
news:uapeltnwHHA.4800@.TK2MSFTNGP05.phx.gbl...
> >The 4 disk raid 5 will get you 3 active spindles for reads which will
> >offer 50% better read throughput than a 4 disk raid 10 set which has only
> >2 active spindles serving data.
> Not quite. While a 4 disk RAID 5 may outperform a 4 disk Raid 10 for
> strictly read operations of large scale it will not be anywhere close to
> 50% in my experience. And don't forget that a smart Raid controller can
> access both disks in the mirrored pair at the same time for different
> operations.
> --
> Andrew J. Kelly SQL MVP
> "TheSQLGuru" <kgboles@.earthlink.net> wrote in message
> news:eeDOTMkwHHA.600@.TK2MSFTNGP05.phx.gbl...
>>I will add one comment to Andrew's suggestion. Consider a 4 disk raid 5
>>set for your data files if the databases are more select oriented than
>>heavy insert/update/delete oriented. The 4 disk raid 5 will get you 3
>>active spindles for reads which will offer 50% better read throughput than
>>a 4 disk raid 10 set which has only 2 active spindles serving data. At
>>least I THINK it works that way. ;)
>> --
>> TheSQLGuru
>> President
>> Indicium Resources, Inc.
>> "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
>> news:O7NP4Q$vHHA.3400@.TK2MSFTNGP03.phx.gbl...
>>I don't know how busy this will be but if you get two more disks and
>>create a Raid 1 I would put the OS and possibly the log files (both user
>>and tempdb) on that array. Then leave the data files on the Raid 10. The
>>OS doesn't get used much and at least you would separate the data and log
>>files.
>> --
>> Andrew J. Kelly SQL MVP
>> "MattieG" <mattiegriffin@.hotmail.co.uk> wrote in message
>> news:1183737319.730417.129770@.c77g2000hse.googlegroups.com...
>> Cool, that confirmed my suspicions :)
>> Im actually looking at getting a couple more disks for the OS or
>> possibly OS+Database
>> and maybe use the raid 10 for the log files only.
>> Unless I use 3 raid 1 arrays for OS / Database / Logfile?
>> Mattie
>>
>>
>>
>|||don't think that raid controler is permitted to perform different tasks on
mirrored disks.
smart [very smart & very expensive] raid controler may perform doubled read
from raid1 array, reading at the same time sector_x from disk_0, and
sector_y from disk_1, so having read two sectors at the time tick of just
one.
for this reason raid controler should have very good knowledge of current
head/track location of each disks, and to manage them separately.
information i found just show that this is rarely a case, mostly raid
controler uses just one of raid1 disks for reading, usualy one having better
response time.
the best thing i found useful is using *outer* cylindres for best
performances. on new disks, 25% of outer cylindres has a 25% better
throughoutput then the rest of disk. so, i made on each disk two partitions,
outer, for quick files transfer/read, and inner, for some backup [to not
waste space].
my sql database is only 20gig,, so the smaller outer partition on larger
disks is quite enough.
for tempdb, which needs quick read/write, but not to survive shutdown, maybe
to use i-ram [it is pc card with 4gb ram, connected to mb as ordinarly sata
drive] since it is very fast, but limited to 4gb, possible to form jbod
disk, i-ram and one regular hd, so to allow tempdb, if overgow the 4gb space
to take place on larger second drive.
just my few observations ...
"TheSQLGuru" <kgboles@.earthlink.net> wrote in message
news:uBYpnj8wHHA.3796@.TK2MSFTNGP04.phx.gbl...
> >>And don't forget that a smart Raid controller can access both disks in
> >>the mirrored pair at the same time for different operations.
> That was the part I wasn't sure about. I didn't know if the controller
> would be able to maintain data integrity if it flipped back and forth
> between the drives accessing different areas for different read/write
> operations.
>|||I haven't gone to that level recently but I remember years ago the DPT raid
controllers used to be able to read from one disk and write to the other at
the same time. It would then do the necessary deferred writes to keep them
in sync of coarse. As long as the cache and types of activities were
compatible it seemed to work just fine. So I assume with more modern
technology this is still true but I can't confirm that for sure.
--
Andrew J. Kelly SQL MVP
"sali" <gabor.salai@.tel.net.ba> wrote in message
news:%236csKJ$wHHA.1208@.TK2MSFTNGP03.phx.gbl...
> don't think that raid controler is permitted to perform different tasks on
> mirrored disks.
> smart [very smart & very expensive] raid controler may perform doubled
> read
> from raid1 array, reading at the same time sector_x from disk_0, and
> sector_y from disk_1, so having read two sectors at the time tick of just
> one.
> for this reason raid controler should have very good knowledge of current
> head/track location of each disks, and to manage them separately.
> information i found just show that this is rarely a case, mostly raid
> controler uses just one of raid1 disks for reading, usualy one having
> better
> response time.
> the best thing i found useful is using *outer* cylindres for best
> performances. on new disks, 25% of outer cylindres has a 25% better
> throughoutput then the rest of disk. so, i made on each disk two
> partitions,
> outer, for quick files transfer/read, and inner, for some backup [to not
> waste space].
> my sql database is only 20gig,, so the smaller outer partition on larger
> disks is quite enough.
> for tempdb, which needs quick read/write, but not to survive shutdown,
> maybe
> to use i-ram [it is pc card with 4gb ram, connected to mb as ordinarly
> sata
> drive] since it is very fast, but limited to 4gb, possible to form jbod
> disk, i-ram and one regular hd, so to allow tempdb, if overgow the 4gb
> space
> to take place on larger second drive.
> just my few observations ...
>
> "TheSQLGuru" <kgboles@.earthlink.net> wrote in message
> news:uBYpnj8wHHA.3796@.TK2MSFTNGP04.phx.gbl...
>> >>And don't forget that a smart Raid controller can access both disks in
>> >>the mirrored pair at the same time for different operations.
>> That was the part I wasn't sure about. I didn't know if the controller
>> would be able to maintain data integrity if it flipped back and forth
>> between the drives accessing different areas for different read/write
>> operations.
>
>
RAID 10 Setup Question
Hi Everyone
I really need some clarification on this issue before I start using
this new server.
It has 4 Drives in a RAID 10 config and I need to know if I should
partition then for the following:
Setup 1 - everything on C: Partiton
Setup 2 - 2 Partitions
C: OS
D: SQL DATA / SQL LOGFILES
Setup 3 - 3 Partitions
C: OS
D: SQL DATA
E: SQL LOG FILES
I would have thought there would be more head movement in 2 and 3
partitions but I may be wrong.
IU know SQL does use all the memory which is fine it has 4 gig but
what does everyone recommend i do?
MattieUsing logical partitions on the same physical drive array do nothing for
performance but can give the illusion as such to people who may not know
that physical layout. If there is no choice but to have a single drive array
I prefer to have only 1 partition. That way there is never a problem if you
made one too large or too small later down the road.
Andrew J. Kelly SQL MVP
"MattieG" <mattiegriffin@.hotmail.co.uk> wrote in message
news:1183731888.891067.55660@.g13g2000hsf.googlegroups.com...
> Hi Everyone
> I really need some clarification on this issue before I start using
> this new server.
> It has 4 Drives in a RAID 10 config and I need to know if I should
> partition then for the following:
> Setup 1 - everything on C: Partiton
> Setup 2 - 2 Partitions
> C: OS
> D: SQL DATA / SQL LOGFILES
> Setup 3 - 3 Partitions
> C: OS
> D: SQL DATA
> E: SQL LOG FILES
> I would have thought there would be more head movement in 2 and 3
> partitions but I may be wrong.
> IU know SQL does use all the memory which is fine it has 4 gig but
> what does everyone recommend i do?
> Mattie
>|||MattieG,
I definitely understand Andrew's contention that unpartitioned is less
deceptive. (And partitioning caused me some serious grief once.)
Do you think you will get leverage to eventually separate the disks so that
you have log files on a different physical array? If so, then partitioning
now will allow your file paths to be set up for the future arrival of real
disks. But, if you do not do it now, it is not difficult to move files in
that happy future day.
RLF
"MattieG" <mattiegriffin@.hotmail.co.uk> wrote in message
news:1183731888.891067.55660@.g13g2000hsf.googlegroups.com...
> Hi Everyone
> I really need some clarification on this issue before I start using
> this new server.
> It has 4 Drives in a RAID 10 config and I need to know if I should
> partition then for the following:
> Setup 1 - everything on C: Partiton
> Setup 2 - 2 Partitions
> C: OS
> D: SQL DATA / SQL LOGFILES
> Setup 3 - 3 Partitions
> C: OS
> D: SQL DATA
> E: SQL LOG FILES
> I would have thought there would be more head movement in 2 and 3
> partitions but I may be wrong.
> IU know SQL does use all the memory which is fine it has 4 gig but
> what does everyone recommend i do?
> Mattie
>|||Cool, that confirmed my suspicions
Im actually looking at getting a couple more disks for the OS or
possibly OS+Database
and maybe use the raid 10 for the log files only.
Unless I use 3 raid 1 arrays for OS / Database / Logfile?
Mattie|||I don't know how busy this will be but if you get two more disks and create
a Raid 1 I would put the OS and possibly the log files (both user and
tempdb) on that array. Then leave the data files on the Raid 10. The OS
doesn't get used much and at least you would separate the data and log
files.
Andrew J. Kelly SQL MVP
"MattieG" <mattiegriffin@.hotmail.co.uk> wrote in message
news:1183737319.730417.129770@.c77g2000hse.googlegroups.com...
> Cool, that confirmed my suspicions
> Im actually looking at getting a couple more disks for the OS or
> possibly OS+Database
> and maybe use the raid 10 for the log files only.
> Unless I use 3 raid 1 arrays for OS / Database / Logfile?
> Mattie
>|||Here is an article I wrote on setting up disk configurations.
http://searchsqlserver.techtarget.c...1262122,00.html
Denny
MCSA (2003) / MCDBA (SQL 2000)
MCTS (SQL 2005 / Microsoft Windows SharePoint Services 3.0: Configuration /
Microsoft Office SharePoint Server 2007: Configuration)
MCITP (dbadmin, dbdev)
"MattieG" wrote:
> Hi Everyone
> I really need some clarification on this issue before I start using
> this new server.
> It has 4 Drives in a RAID 10 config and I need to know if I should
> partition then for the following:
> Setup 1 - everything on C: Partiton
> Setup 2 - 2 Partitions
> C: OS
> D: SQL DATA / SQL LOGFILES
> Setup 3 - 3 Partitions
> C: OS
> D: SQL DATA
> E: SQL LOG FILES
> I would have thought there would be more head movement in 2 and 3
> partitions but I may be wrong.
> IU know SQL does use all the memory which is fine it has 4 gig but
> what does everyone recommend i do?
> Mattie
>|||?Hi
Thanks for everything I will order some more disks.
Mattie|||I will add one comment to Andrew's suggestion. Consider a 4 disk raid 5 set
for your data files if the databases are more select oriented than heavy
insert/update/delete oriented. The 4 disk raid 5 will get you 3 active
spindles for reads which will offer 50% better read throughput than a 4 disk
raid 10 set which has only 2 active spindles serving data. At least I THINK
it works that way. ;)
TheSQLGuru
President
Indicium Resources, Inc.
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
news:O7NP4Q$vHHA.3400@.TK2MSFTNGP03.phx.gbl...
>I don't know how busy this will be but if you get two more disks and create
>a Raid 1 I would put the OS and possibly the log files (both user and
>tempdb) on that array. Then leave the data files on the Raid 10. The OS
>doesn't get used much and at least you would separate the data and log
>files.
> --
> Andrew J. Kelly SQL MVP
> "MattieG" <mattiegriffin@.hotmail.co.uk> wrote in message
> news:1183737319.730417.129770@.c77g2000hse.googlegroups.com...
>|||>The 4 disk raid 5 will get you 3 active spindles for reads which will offer
>50% better read throughput than a 4 disk raid 10 set which has only 2
>active spindles serving data.
Not quite. While a 4 disk RAID 5 may outperform a 4 disk Raid 10 for
strictly read operations of large scale it will not be anywhere close to 50%
in my experience. And don't forget that a smart Raid controller can access
both disks in the mirrored pair at the same time for different operations.
Andrew J. Kelly SQL MVP
"TheSQLGuru" <kgboles@.earthlink.net> wrote in message
news:eeDOTMkwHHA.600@.TK2MSFTNGP05.phx.gbl...
>I will add one comment to Andrew's suggestion. Consider a 4 disk raid 5
>set for your data files if the databases are more select oriented than
>heavy insert/update/delete oriented. The 4 disk raid 5 will get you 3
>active spindles for reads which will offer 50% better read throughput than
>a 4 disk raid 10 set which has only 2 active spindles serving data. At
>least I THINK it works that way. ;)
> --
> TheSQLGuru
> President
> Indicium Resources, Inc.
> "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
> news:O7NP4Q$vHHA.3400@.TK2MSFTNGP03.phx.gbl...
>|||>>And don't forget that a smart Raid controller can access both disks in
That was the part I wasn't sure about. I didn't know if the controller
would be able to maintain data integrity if it flipped back and forth
between the drives accessing different areas for different read/write
operations.
TheSQLGuru
President
Indicium Resources, Inc.
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
news:uapeltnwHHA.4800@.TK2MSFTNGP05.phx.gbl...[vbcol=seagreen]
> Not quite. While a 4 disk RAID 5 may outperform a 4 disk Raid 10 for
> strictly read operations of large scale it will not be anywhere close to
> 50% in my experience. And don't forget that a smart Raid controller can
> access both disks in the mirrored pair at the same time for different
> operations.
> --
> Andrew J. Kelly SQL MVP
> "TheSQLGuru" <kgboles@.earthlink.net> wrote in message
> news:eeDOTMkwHHA.600@.TK2MSFTNGP05.phx.gbl...
>
I really need some clarification on this issue before I start using
this new server.
It has 4 Drives in a RAID 10 config and I need to know if I should
partition then for the following:
Setup 1 - everything on C: Partiton
Setup 2 - 2 Partitions
C: OS
D: SQL DATA / SQL LOGFILES
Setup 3 - 3 Partitions
C: OS
D: SQL DATA
E: SQL LOG FILES
I would have thought there would be more head movement in 2 and 3
partitions but I may be wrong.
IU know SQL does use all the memory which is fine it has 4 gig but
what does everyone recommend i do?
MattieUsing logical partitions on the same physical drive array do nothing for
performance but can give the illusion as such to people who may not know
that physical layout. If there is no choice but to have a single drive array
I prefer to have only 1 partition. That way there is never a problem if you
made one too large or too small later down the road.
Andrew J. Kelly SQL MVP
"MattieG" <mattiegriffin@.hotmail.co.uk> wrote in message
news:1183731888.891067.55660@.g13g2000hsf.googlegroups.com...
> Hi Everyone
> I really need some clarification on this issue before I start using
> this new server.
> It has 4 Drives in a RAID 10 config and I need to know if I should
> partition then for the following:
> Setup 1 - everything on C: Partiton
> Setup 2 - 2 Partitions
> C: OS
> D: SQL DATA / SQL LOGFILES
> Setup 3 - 3 Partitions
> C: OS
> D: SQL DATA
> E: SQL LOG FILES
> I would have thought there would be more head movement in 2 and 3
> partitions but I may be wrong.
> IU know SQL does use all the memory which is fine it has 4 gig but
> what does everyone recommend i do?
> Mattie
>|||MattieG,
I definitely understand Andrew's contention that unpartitioned is less
deceptive. (And partitioning caused me some serious grief once.)
Do you think you will get leverage to eventually separate the disks so that
you have log files on a different physical array? If so, then partitioning
now will allow your file paths to be set up for the future arrival of real
disks. But, if you do not do it now, it is not difficult to move files in
that happy future day.
RLF
"MattieG" <mattiegriffin@.hotmail.co.uk> wrote in message
news:1183731888.891067.55660@.g13g2000hsf.googlegroups.com...
> Hi Everyone
> I really need some clarification on this issue before I start using
> this new server.
> It has 4 Drives in a RAID 10 config and I need to know if I should
> partition then for the following:
> Setup 1 - everything on C: Partiton
> Setup 2 - 2 Partitions
> C: OS
> D: SQL DATA / SQL LOGFILES
> Setup 3 - 3 Partitions
> C: OS
> D: SQL DATA
> E: SQL LOG FILES
> I would have thought there would be more head movement in 2 and 3
> partitions but I may be wrong.
> IU know SQL does use all the memory which is fine it has 4 gig but
> what does everyone recommend i do?
> Mattie
>|||Cool, that confirmed my suspicions
Im actually looking at getting a couple more disks for the OS or
possibly OS+Database
and maybe use the raid 10 for the log files only.
Unless I use 3 raid 1 arrays for OS / Database / Logfile?
Mattie|||I don't know how busy this will be but if you get two more disks and create
a Raid 1 I would put the OS and possibly the log files (both user and
tempdb) on that array. Then leave the data files on the Raid 10. The OS
doesn't get used much and at least you would separate the data and log
files.
Andrew J. Kelly SQL MVP
"MattieG" <mattiegriffin@.hotmail.co.uk> wrote in message
news:1183737319.730417.129770@.c77g2000hse.googlegroups.com...
> Cool, that confirmed my suspicions
> Im actually looking at getting a couple more disks for the OS or
> possibly OS+Database
> and maybe use the raid 10 for the log files only.
> Unless I use 3 raid 1 arrays for OS / Database / Logfile?
> Mattie
>|||Here is an article I wrote on setting up disk configurations.
http://searchsqlserver.techtarget.c...1262122,00.html
Denny
MCSA (2003) / MCDBA (SQL 2000)
MCTS (SQL 2005 / Microsoft Windows SharePoint Services 3.0: Configuration /
Microsoft Office SharePoint Server 2007: Configuration)
MCITP (dbadmin, dbdev)
"MattieG" wrote:
> Hi Everyone
> I really need some clarification on this issue before I start using
> this new server.
> It has 4 Drives in a RAID 10 config and I need to know if I should
> partition then for the following:
> Setup 1 - everything on C: Partiton
> Setup 2 - 2 Partitions
> C: OS
> D: SQL DATA / SQL LOGFILES
> Setup 3 - 3 Partitions
> C: OS
> D: SQL DATA
> E: SQL LOG FILES
> I would have thought there would be more head movement in 2 and 3
> partitions but I may be wrong.
> IU know SQL does use all the memory which is fine it has 4 gig but
> what does everyone recommend i do?
> Mattie
>|||?Hi
Thanks for everything
I will order some more disks.Mattie|||I will add one comment to Andrew's suggestion. Consider a 4 disk raid 5 set
for your data files if the databases are more select oriented than heavy
insert/update/delete oriented. The 4 disk raid 5 will get you 3 active
spindles for reads which will offer 50% better read throughput than a 4 disk
raid 10 set which has only 2 active spindles serving data. At least I THINK
it works that way. ;)
TheSQLGuru
President
Indicium Resources, Inc.
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
news:O7NP4Q$vHHA.3400@.TK2MSFTNGP03.phx.gbl...
>I don't know how busy this will be but if you get two more disks and create
>a Raid 1 I would put the OS and possibly the log files (both user and
>tempdb) on that array. Then leave the data files on the Raid 10. The OS
>doesn't get used much and at least you would separate the data and log
>files.
> --
> Andrew J. Kelly SQL MVP
> "MattieG" <mattiegriffin@.hotmail.co.uk> wrote in message
> news:1183737319.730417.129770@.c77g2000hse.googlegroups.com...
>|||>The 4 disk raid 5 will get you 3 active spindles for reads which will offer
>50% better read throughput than a 4 disk raid 10 set which has only 2
>active spindles serving data.
Not quite. While a 4 disk RAID 5 may outperform a 4 disk Raid 10 for
strictly read operations of large scale it will not be anywhere close to 50%
in my experience. And don't forget that a smart Raid controller can access
both disks in the mirrored pair at the same time for different operations.
Andrew J. Kelly SQL MVP
"TheSQLGuru" <kgboles@.earthlink.net> wrote in message
news:eeDOTMkwHHA.600@.TK2MSFTNGP05.phx.gbl...
>I will add one comment to Andrew's suggestion. Consider a 4 disk raid 5
>set for your data files if the databases are more select oriented than
>heavy insert/update/delete oriented. The 4 disk raid 5 will get you 3
>active spindles for reads which will offer 50% better read throughput than
>a 4 disk raid 10 set which has only 2 active spindles serving data. At
>least I THINK it works that way. ;)
> --
> TheSQLGuru
> President
> Indicium Resources, Inc.
> "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
> news:O7NP4Q$vHHA.3400@.TK2MSFTNGP03.phx.gbl...
>|||>>And don't forget that a smart Raid controller can access both disks in
That was the part I wasn't sure about. I didn't know if the controller
would be able to maintain data integrity if it flipped back and forth
between the drives accessing different areas for different read/write
operations.
TheSQLGuru
President
Indicium Resources, Inc.
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
news:uapeltnwHHA.4800@.TK2MSFTNGP05.phx.gbl...[vbcol=seagreen]
> Not quite. While a 4 disk RAID 5 may outperform a 4 disk Raid 10 for
> strictly read operations of large scale it will not be anywhere close to
> 50% in my experience. And don't forget that a smart Raid controller can
> access both disks in the mirrored pair at the same time for different
> operations.
> --
> Andrew J. Kelly SQL MVP
> "TheSQLGuru" <kgboles@.earthlink.net> wrote in message
> news:eeDOTMkwHHA.600@.TK2MSFTNGP05.phx.gbl...
>
Raid 10 or Raid 5?
Is raid 10 better than 5 with only 3 h/drives. Does no of h/drives matter ?Yes it does matter.
Raid 10 is faster than Raid 5, however it will need twice
the number of disks. So if you have two disjs of 10 gb
each, the most you can get out of them is 10 gb NOT 20.
Raid 5 is slower but is better with disks so you will get
more space.
As you only have a couple of disks I sugest raid 5
J
>--Original Message--
>Is raid 10 better than 5 with only 3 h/drives. Does no of
h/drives matter ?
>.
>|||depends on your needs. If READ is the primary function, RAID5 makes
sense because its less costly, but write is primary function
RAID10(0+1) is the best solution.|||But she can't do a RAID 10 with just 3 drives. It's either a Raid 1 and you
loose a drive or Raid 5.
--
Andrew J. Kelly
SQL Server MVP
<sightdev@.yahoo.com> wrote in message
news:9861f5eb.0401300736.6761b95d@.posting.google.com...
> depends on your needs. If READ is the primary function, RAID5 makes
> sense because its less costly, but write is primary function
> RAID10(0+1) is the best solution.|||A word of warning. I discovered my expensive Dell Perc3/DC controllers
implement Raid 10 as a span (concatenation) of mirrors not a stripe.
I have 22 disks and over half are idle.
I'm having to split the database file and log file into pieces.
Paul
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
news:ucSRJy05DHA.2560@.TK2MSFTNGP09.phx.gbl...
> But she can't do a RAID 10 with just 3 drives. It's either a Raid 1 and
you
> loose a drive or Raid 5.
> --
> Andrew J. Kelly
> SQL Server MVP
>
> <sightdev@.yahoo.com> wrote in message
> news:9861f5eb.0401300736.6761b95d@.posting.google.com...
> > depends on your needs. If READ is the primary function, RAID5 makes
> > sense because its less costly, but write is primary function
> > RAID10(0+1) is the best solution.
>|||Paul,
Not sure what you mean exactly. The RAID numbers often get confusing when
it comes to 1+0 or 0+1. One will be a stripe of mirrors and the other is a
mirror of stripes. The difference is mainly in the redundancy as the stripe
of mirrors will tolerate potentially more failures than a mirror of stripes.
In either case all the disks are used but you only get half the usable disk
space. That is how Raid arrays work. You sacrifice drives for redundancy
and speed. I don't know why you say you need to split your files. That
should not be necessary.
--
Andrew J. Kelly
SQL Server MVP
"Paul Cahill" <XYZpaul.cahillXYZ@.blueyonder.co.uk> wrote in message
news:eyHa3nY6DHA.2264@.tk2msftngp13.phx.gbl...
> A word of warning. I discovered my expensive Dell Perc3/DC controllers
> implement Raid 10 as a span (concatenation) of mirrors not a stripe.
> I have 22 disks and over half are idle.
> I'm having to split the database file and log file into pieces.
> Paul
>
> "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
> news:ucSRJy05DHA.2560@.TK2MSFTNGP09.phx.gbl...
> > But she can't do a RAID 10 with just 3 drives. It's either a Raid 1 and
> you
> > loose a drive or Raid 5.
> >
> > --
> >
> > Andrew J. Kelly
> > SQL Server MVP
> >
> >
> > <sightdev@.yahoo.com> wrote in message
> > news:9861f5eb.0401300736.6761b95d@.posting.google.com...
> > > depends on your needs. If READ is the primary function, RAID5 makes
> > > sense because its less costly, but write is primary function
> > > RAID10(0+1) is the best solution.
> >
> >
>|||You are correct on the raid levels and raid 10 is defined as a stripe of
mirrors. However Dell's documentation for the Perc3 and other controllers
now states (and it's true) that their implementation of raid 10 is a span of
mirrors. ie if you have a raid 10 of four 18GB disks and you create a 9GB
log file the file will wholy reside on the first mirror pair. The second
mirror pair will not be used until the 1st mirror pair is full.
This explains the dissappointing performance we have from our 22 disk
system. Although I benchmarked it, the one thing I did not do when I set it
up was to watch the disk lights.
For example our log file does indeed live on a 4 disk raid 10 array of 18GB
15K drives. The log file is smaller than 18GB. When I/O occurs only two of
the disk lights flash. The other two never flash. If it was true raid 10
then all 4 lights should flash as the i/o is striped.
So I'm having to do the striping myself by spitting the files across raid
arrays. ie Indexes on one, certain tables on another. Not a bad thing
anyway I guess. But if I'd known about dell's Raid 10 I'd have planned
differently. It's not east to make changes on a 24/7 system.
An alternative with the dell perc3 would be to stripe the drives (Raid 0)
and then mirror using the O/S. Not one I care to choose.
Paul
http://docs.us.dell.com/docs/storage/perc3dc/ug/en/Levels.htm
The above document describes Raid 10 on the perc3/dc as a stripe of mirrors
http://docs.us.dell.com/docs/software/smarrman/marb32/ch8_perc.htm
This document shows that perc3/dc implements as a concatenation
Search for string "Supported RAID Levels for PERC Subsystem Controllers"
http://docs.us.dell.com/docs/software/smarrman/marb32/ch3_stor.htm#1037893
This document describes spanned disks
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
news:uXdx2uZ6DHA.2952@.TK2MSFTNGP09.phx.gbl...
> Paul,
> Not sure what you mean exactly. The RAID numbers often get confusing when
> it comes to 1+0 or 0+1. One will be a stripe of mirrors and the other is
a
> mirror of stripes. The difference is mainly in the redundancy as the
stripe
> of mirrors will tolerate potentially more failures than a mirror of
stripes.
> In either case all the disks are used but you only get half the usable
disk
> space. That is how Raid arrays work. You sacrifice drives for redundancy
> and speed. I don't know why you say you need to split your files. That
> should not be necessary.
> --
> Andrew J. Kelly
> SQL Server MVP
>
> "Paul Cahill" <XYZpaul.cahillXYZ@.blueyonder.co.uk> wrote in message
> news:eyHa3nY6DHA.2264@.tk2msftngp13.phx.gbl...
> > A word of warning. I discovered my expensive Dell Perc3/DC controllers
> > implement Raid 10 as a span (concatenation) of mirrors not a stripe.
> > I have 22 disks and over half are idle.
> > I'm having to split the database file and log file into pieces.
> >
> > Paul
> >
> >
> > "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
> > news:ucSRJy05DHA.2560@.TK2MSFTNGP09.phx.gbl...
> > > But she can't do a RAID 10 with just 3 drives. It's either a Raid 1
and
> > you
> > > loose a drive or Raid 5.
> > >
> > > --
> > >
> > > Andrew J. Kelly
> > > SQL Server MVP
> > >
> > >
> > > <sightdev@.yahoo.com> wrote in message
> > > news:9861f5eb.0401300736.6761b95d@.posting.google.com...
> > > > depends on your needs. If READ is the primary function, RAID5 makes
> > > > sense because its less costly, but write is primary function
> > > > RAID10(0+1) is the best solution.
> > >
> > >
> >
> >
>|||Paul,
I have to admit I don't know exactly what they are referring to. Hopefully
I can read more on it later but it doesn't sound pretty. I would call and
talk to someone in tech support directly who says claims they know what they
are talking about when it comes to this implementation of RAID 10 to get his
take. If it's anything close to what the docs state I would ask for my
money back since that is no where close to the definition of RAID 10 that I
have ever seen and I don't know how they can even claim it as such. From
what I gather the reason why the other disks lights are not blinking is that
with "concatenation" it fills up the first disk before it moves to the next
and you probably don't have enough data on it yet. Hopefully we are just
misreading their information but in either case I wish you luck.
Andrew J. Kelly
SQL Server MVP
"Paul Cahill" <XYZpaul.cahillXYZ@.blueyonder.co.uk> wrote in message
news:OYmMKUj6DHA.1936@.TK2MSFTNGP12.phx.gbl...
> You are correct on the raid levels and raid 10 is defined as a stripe of
> mirrors. However Dell's documentation for the Perc3 and other controllers
> now states (and it's true) that their implementation of raid 10 is a span
of
> mirrors. ie if you have a raid 10 of four 18GB disks and you create a 9GB
> log file the file will wholy reside on the first mirror pair. The second
> mirror pair will not be used until the 1st mirror pair is full.
> This explains the dissappointing performance we have from our 22 disk
> system. Although I benchmarked it, the one thing I did not do when I set
it
> up was to watch the disk lights.
> For example our log file does indeed live on a 4 disk raid 10 array of
18GB
> 15K drives. The log file is smaller than 18GB. When I/O occurs only two of
> the disk lights flash. The other two never flash. If it was true raid 10
> then all 4 lights should flash as the i/o is striped.
> So I'm having to do the striping myself by spitting the files across raid
> arrays. ie Indexes on one, certain tables on another. Not a bad thing
> anyway I guess. But if I'd known about dell's Raid 10 I'd have planned
> differently. It's not east to make changes on a 24/7 system.
> An alternative with the dell perc3 would be to stripe the drives (Raid 0)
> and then mirror using the O/S. Not one I care to choose.
> Paul
> http://docs.us.dell.com/docs/storage/perc3dc/ug/en/Levels.htm
> The above document describes Raid 10 on the perc3/dc as a stripe of
mirrors
>
> http://docs.us.dell.com/docs/software/smarrman/marb32/ch8_perc.htm
> This document shows that perc3/dc implements as a concatenation
> Search for string "Supported RAID Levels for PERC Subsystem Controllers"
>
> http://docs.us.dell.com/docs/software/smarrman/marb32/ch3_stor.htm#1037893
> This document describes spanned disks
>
> "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
> news:uXdx2uZ6DHA.2952@.TK2MSFTNGP09.phx.gbl...
> > Paul,
> >
> > Not sure what you mean exactly. The RAID numbers often get confusing
when
> > it comes to 1+0 or 0+1. One will be a stripe of mirrors and the other
is
> a
> > mirror of stripes. The difference is mainly in the redundancy as the
> stripe
> > of mirrors will tolerate potentially more failures than a mirror of
> stripes.
> > In either case all the disks are used but you only get half the usable
> disk
> > space. That is how Raid arrays work. You sacrifice drives for
redundancy
> > and speed. I don't know why you say you need to split your files. That
> > should not be necessary.
> >
> > --
> >
> > Andrew J. Kelly
> > SQL Server MVP
> >
> >
> > "Paul Cahill" <XYZpaul.cahillXYZ@.blueyonder.co.uk> wrote in message
> > news:eyHa3nY6DHA.2264@.tk2msftngp13.phx.gbl...
> > > A word of warning. I discovered my expensive Dell Perc3/DC controllers
> > > implement Raid 10 as a span (concatenation) of mirrors not a stripe.
> > > I have 22 disks and over half are idle.
> > > I'm having to split the database file and log file into pieces.
> > >
> > > Paul
> > >
> > >
> > > "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
> > > news:ucSRJy05DHA.2560@.TK2MSFTNGP09.phx.gbl...
> > > > But she can't do a RAID 10 with just 3 drives. It's either a Raid 1
> and
> > > you
> > > > loose a drive or Raid 5.
> > > >
> > > > --
> > > >
> > > > Andrew J. Kelly
> > > > SQL Server MVP
> > > >
> > > >
> > > > <sightdev@.yahoo.com> wrote in message
> > > > news:9861f5eb.0401300736.6761b95d@.posting.google.com...
> > > > > depends on your needs. If READ is the primary function, RAID5
makes
> > > > > sense because its less costly, but write is primary function
> > > > > RAID10(0+1) is the best solution.
> > > >
> > > >
> > >
> > >
> >
> >
>|||I am taking this up with Dell, others are discussing this in the Dell Talk
forum.
The sales guys and the 1st line tech support people don't even understand
the issue.
At the moment I'm getting unfufilled call back promises.
My main data file is on a (Dell) raid 10 of 6 disks 18GB disks. The main
data file is over 36GB. If I watch the lights on this logical array they do
all flash but not together. You can see it happening in pairs. If I/O on the
data file was truly random then I would be getting some bangs for all my
bucks but of course there are always hotspots in data access.
No single i/o will ever proceed faster than the speed of a single 18GB 15K
drive.
The only way I can see around this is to stripe using the perc3 and then
mirror the stripe using the operating system. Not a route I am prepared to
proceed with.
Paul
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
news:eImaq%23l6DHA.2480@.TK2MSFTNGP10.phx.gbl...
> Paul,
> I have to admit I don't know exactly what they are referring to.
Hopefully
> I can read more on it later but it doesn't sound pretty. I would call and
> talk to someone in tech support directly who says claims they know what
they
> are talking about when it comes to this implementation of RAID 10 to get
his
> take. If it's anything close to what the docs state I would ask for my
> money back since that is no where close to the definition of RAID 10 that
I
> have ever seen and I don't know how they can even claim it as such. From
> what I gather the reason why the other disks lights are not blinking is
that
> with "concatenation" it fills up the first disk before it moves to the
next
> and you probably don't have enough data on it yet. Hopefully we are just
> misreading their information but in either case I wish you luck.
>
>
> --
> Andrew J. Kelly
> SQL Server MVP
>
> "Paul Cahill" <XYZpaul.cahillXYZ@.blueyonder.co.uk> wrote in message
> news:OYmMKUj6DHA.1936@.TK2MSFTNGP12.phx.gbl...
> > You are correct on the raid levels and raid 10 is defined as a stripe of
> > mirrors. However Dell's documentation for the Perc3 and other
controllers
> > now states (and it's true) that their implementation of raid 10 is a
span
> of
> > mirrors. ie if you have a raid 10 of four 18GB disks and you create a
9GB
> > log file the file will wholy reside on the first mirror pair. The
second
> > mirror pair will not be used until the 1st mirror pair is full.
> >
> > This explains the dissappointing performance we have from our 22 disk
> > system. Although I benchmarked it, the one thing I did not do when I set
> it
> > up was to watch the disk lights.
> > For example our log file does indeed live on a 4 disk raid 10 array of
> 18GB
> > 15K drives. The log file is smaller than 18GB. When I/O occurs only two
of
> > the disk lights flash. The other two never flash. If it was true raid 10
> > then all 4 lights should flash as the i/o is striped.
> >
> > So I'm having to do the striping myself by spitting the files across
raid
> > arrays. ie Indexes on one, certain tables on another. Not a bad thing
> > anyway I guess. But if I'd known about dell's Raid 10 I'd have planned
> > differently. It's not east to make changes on a 24/7 system.
> >
> > An alternative with the dell perc3 would be to stripe the drives (Raid
0)
> > and then mirror using the O/S. Not one I care to choose.
> >
> > Paul
> >
> > http://docs.us.dell.com/docs/storage/perc3dc/ug/en/Levels.htm
> > The above document describes Raid 10 on the perc3/dc as a stripe of
> mirrors
> >
> >
> > http://docs.us.dell.com/docs/software/smarrman/marb32/ch8_perc.htm
> > This document shows that perc3/dc implements as a concatenation
> > Search for string "Supported RAID Levels for PERC Subsystem Controllers"
> >
> >
> >
http://docs.us.dell.com/docs/software/smarrman/marb32/ch3_stor.htm#1037893
> > This document describes spanned disks
> >
> >
> > "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
> > news:uXdx2uZ6DHA.2952@.TK2MSFTNGP09.phx.gbl...
> > > Paul,
> > >
> > > Not sure what you mean exactly. The RAID numbers often get confusing
> when
> > > it comes to 1+0 or 0+1. One will be a stripe of mirrors and the other
> is
> > a
> > > mirror of stripes. The difference is mainly in the redundancy as the
> > stripe
> > > of mirrors will tolerate potentially more failures than a mirror of
> > stripes.
> > > In either case all the disks are used but you only get half the usable
> > disk
> > > space. That is how Raid arrays work. You sacrifice drives for
> redundancy
> > > and speed. I don't know why you say you need to split your files.
That
> > > should not be necessary.
> > >
> > > --
> > >
> > > Andrew J. Kelly
> > > SQL Server MVP
> > >
> > >
> > > "Paul Cahill" <XYZpaul.cahillXYZ@.blueyonder.co.uk> wrote in message
> > > news:eyHa3nY6DHA.2264@.tk2msftngp13.phx.gbl...
> > > > A word of warning. I discovered my expensive Dell Perc3/DC
controllers
> > > > implement Raid 10 as a span (concatenation) of mirrors not a stripe.
> > > > I have 22 disks and over half are idle.
> > > > I'm having to split the database file and log file into pieces.
> > > >
> > > > Paul
> > > >
> > > >
> > > > "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
> > > > news:ucSRJy05DHA.2560@.TK2MSFTNGP09.phx.gbl...
> > > > > But she can't do a RAID 10 with just 3 drives. It's either a Raid
1
> > and
> > > > you
> > > > > loose a drive or Raid 5.
> > > > >
> > > > > --
> > > > >
> > > > > Andrew J. Kelly
> > > > > SQL Server MVP
> > > > >
> > > > >
> > > > > <sightdev@.yahoo.com> wrote in message
> > > > > news:9861f5eb.0401300736.6761b95d@.posting.google.com...
> > > > > > depends on your needs. If READ is the primary function, RAID5
> makes
> > > > > > sense because its less costly, but write is primary function
> > > > > > RAID10(0+1) is the best solution.
> > > > >
> > > > >
> > > >
> > > >
> > >
> > >
> >
> >
>
Raid 10 is faster than Raid 5, however it will need twice
the number of disks. So if you have two disjs of 10 gb
each, the most you can get out of them is 10 gb NOT 20.
Raid 5 is slower but is better with disks so you will get
more space.
As you only have a couple of disks I sugest raid 5
J
>--Original Message--
>Is raid 10 better than 5 with only 3 h/drives. Does no of
h/drives matter ?
>.
>|||depends on your needs. If READ is the primary function, RAID5 makes
sense because its less costly, but write is primary function
RAID10(0+1) is the best solution.|||But she can't do a RAID 10 with just 3 drives. It's either a Raid 1 and you
loose a drive or Raid 5.
--
Andrew J. Kelly
SQL Server MVP
<sightdev@.yahoo.com> wrote in message
news:9861f5eb.0401300736.6761b95d@.posting.google.com...
> depends on your needs. If READ is the primary function, RAID5 makes
> sense because its less costly, but write is primary function
> RAID10(0+1) is the best solution.|||A word of warning. I discovered my expensive Dell Perc3/DC controllers
implement Raid 10 as a span (concatenation) of mirrors not a stripe.
I have 22 disks and over half are idle.
I'm having to split the database file and log file into pieces.
Paul
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
news:ucSRJy05DHA.2560@.TK2MSFTNGP09.phx.gbl...
> But she can't do a RAID 10 with just 3 drives. It's either a Raid 1 and
you
> loose a drive or Raid 5.
> --
> Andrew J. Kelly
> SQL Server MVP
>
> <sightdev@.yahoo.com> wrote in message
> news:9861f5eb.0401300736.6761b95d@.posting.google.com...
> > depends on your needs. If READ is the primary function, RAID5 makes
> > sense because its less costly, but write is primary function
> > RAID10(0+1) is the best solution.
>|||Paul,
Not sure what you mean exactly. The RAID numbers often get confusing when
it comes to 1+0 or 0+1. One will be a stripe of mirrors and the other is a
mirror of stripes. The difference is mainly in the redundancy as the stripe
of mirrors will tolerate potentially more failures than a mirror of stripes.
In either case all the disks are used but you only get half the usable disk
space. That is how Raid arrays work. You sacrifice drives for redundancy
and speed. I don't know why you say you need to split your files. That
should not be necessary.
--
Andrew J. Kelly
SQL Server MVP
"Paul Cahill" <XYZpaul.cahillXYZ@.blueyonder.co.uk> wrote in message
news:eyHa3nY6DHA.2264@.tk2msftngp13.phx.gbl...
> A word of warning. I discovered my expensive Dell Perc3/DC controllers
> implement Raid 10 as a span (concatenation) of mirrors not a stripe.
> I have 22 disks and over half are idle.
> I'm having to split the database file and log file into pieces.
> Paul
>
> "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
> news:ucSRJy05DHA.2560@.TK2MSFTNGP09.phx.gbl...
> > But she can't do a RAID 10 with just 3 drives. It's either a Raid 1 and
> you
> > loose a drive or Raid 5.
> >
> > --
> >
> > Andrew J. Kelly
> > SQL Server MVP
> >
> >
> > <sightdev@.yahoo.com> wrote in message
> > news:9861f5eb.0401300736.6761b95d@.posting.google.com...
> > > depends on your needs. If READ is the primary function, RAID5 makes
> > > sense because its less costly, but write is primary function
> > > RAID10(0+1) is the best solution.
> >
> >
>|||You are correct on the raid levels and raid 10 is defined as a stripe of
mirrors. However Dell's documentation for the Perc3 and other controllers
now states (and it's true) that their implementation of raid 10 is a span of
mirrors. ie if you have a raid 10 of four 18GB disks and you create a 9GB
log file the file will wholy reside on the first mirror pair. The second
mirror pair will not be used until the 1st mirror pair is full.
This explains the dissappointing performance we have from our 22 disk
system. Although I benchmarked it, the one thing I did not do when I set it
up was to watch the disk lights.
For example our log file does indeed live on a 4 disk raid 10 array of 18GB
15K drives. The log file is smaller than 18GB. When I/O occurs only two of
the disk lights flash. The other two never flash. If it was true raid 10
then all 4 lights should flash as the i/o is striped.
So I'm having to do the striping myself by spitting the files across raid
arrays. ie Indexes on one, certain tables on another. Not a bad thing
anyway I guess. But if I'd known about dell's Raid 10 I'd have planned
differently. It's not east to make changes on a 24/7 system.
An alternative with the dell perc3 would be to stripe the drives (Raid 0)
and then mirror using the O/S. Not one I care to choose.
Paul
http://docs.us.dell.com/docs/storage/perc3dc/ug/en/Levels.htm
The above document describes Raid 10 on the perc3/dc as a stripe of mirrors
http://docs.us.dell.com/docs/software/smarrman/marb32/ch8_perc.htm
This document shows that perc3/dc implements as a concatenation
Search for string "Supported RAID Levels for PERC Subsystem Controllers"
http://docs.us.dell.com/docs/software/smarrman/marb32/ch3_stor.htm#1037893
This document describes spanned disks
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
news:uXdx2uZ6DHA.2952@.TK2MSFTNGP09.phx.gbl...
> Paul,
> Not sure what you mean exactly. The RAID numbers often get confusing when
> it comes to 1+0 or 0+1. One will be a stripe of mirrors and the other is
a
> mirror of stripes. The difference is mainly in the redundancy as the
stripe
> of mirrors will tolerate potentially more failures than a mirror of
stripes.
> In either case all the disks are used but you only get half the usable
disk
> space. That is how Raid arrays work. You sacrifice drives for redundancy
> and speed. I don't know why you say you need to split your files. That
> should not be necessary.
> --
> Andrew J. Kelly
> SQL Server MVP
>
> "Paul Cahill" <XYZpaul.cahillXYZ@.blueyonder.co.uk> wrote in message
> news:eyHa3nY6DHA.2264@.tk2msftngp13.phx.gbl...
> > A word of warning. I discovered my expensive Dell Perc3/DC controllers
> > implement Raid 10 as a span (concatenation) of mirrors not a stripe.
> > I have 22 disks and over half are idle.
> > I'm having to split the database file and log file into pieces.
> >
> > Paul
> >
> >
> > "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
> > news:ucSRJy05DHA.2560@.TK2MSFTNGP09.phx.gbl...
> > > But she can't do a RAID 10 with just 3 drives. It's either a Raid 1
and
> > you
> > > loose a drive or Raid 5.
> > >
> > > --
> > >
> > > Andrew J. Kelly
> > > SQL Server MVP
> > >
> > >
> > > <sightdev@.yahoo.com> wrote in message
> > > news:9861f5eb.0401300736.6761b95d@.posting.google.com...
> > > > depends on your needs. If READ is the primary function, RAID5 makes
> > > > sense because its less costly, but write is primary function
> > > > RAID10(0+1) is the best solution.
> > >
> > >
> >
> >
>|||Paul,
I have to admit I don't know exactly what they are referring to. Hopefully
I can read more on it later but it doesn't sound pretty. I would call and
talk to someone in tech support directly who says claims they know what they
are talking about when it comes to this implementation of RAID 10 to get his
take. If it's anything close to what the docs state I would ask for my
money back since that is no where close to the definition of RAID 10 that I
have ever seen and I don't know how they can even claim it as such. From
what I gather the reason why the other disks lights are not blinking is that
with "concatenation" it fills up the first disk before it moves to the next
and you probably don't have enough data on it yet. Hopefully we are just
misreading their information but in either case I wish you luck.
Andrew J. Kelly
SQL Server MVP
"Paul Cahill" <XYZpaul.cahillXYZ@.blueyonder.co.uk> wrote in message
news:OYmMKUj6DHA.1936@.TK2MSFTNGP12.phx.gbl...
> You are correct on the raid levels and raid 10 is defined as a stripe of
> mirrors. However Dell's documentation for the Perc3 and other controllers
> now states (and it's true) that their implementation of raid 10 is a span
of
> mirrors. ie if you have a raid 10 of four 18GB disks and you create a 9GB
> log file the file will wholy reside on the first mirror pair. The second
> mirror pair will not be used until the 1st mirror pair is full.
> This explains the dissappointing performance we have from our 22 disk
> system. Although I benchmarked it, the one thing I did not do when I set
it
> up was to watch the disk lights.
> For example our log file does indeed live on a 4 disk raid 10 array of
18GB
> 15K drives. The log file is smaller than 18GB. When I/O occurs only two of
> the disk lights flash. The other two never flash. If it was true raid 10
> then all 4 lights should flash as the i/o is striped.
> So I'm having to do the striping myself by spitting the files across raid
> arrays. ie Indexes on one, certain tables on another. Not a bad thing
> anyway I guess. But if I'd known about dell's Raid 10 I'd have planned
> differently. It's not east to make changes on a 24/7 system.
> An alternative with the dell perc3 would be to stripe the drives (Raid 0)
> and then mirror using the O/S. Not one I care to choose.
> Paul
> http://docs.us.dell.com/docs/storage/perc3dc/ug/en/Levels.htm
> The above document describes Raid 10 on the perc3/dc as a stripe of
mirrors
>
> http://docs.us.dell.com/docs/software/smarrman/marb32/ch8_perc.htm
> This document shows that perc3/dc implements as a concatenation
> Search for string "Supported RAID Levels for PERC Subsystem Controllers"
>
> http://docs.us.dell.com/docs/software/smarrman/marb32/ch3_stor.htm#1037893
> This document describes spanned disks
>
> "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
> news:uXdx2uZ6DHA.2952@.TK2MSFTNGP09.phx.gbl...
> > Paul,
> >
> > Not sure what you mean exactly. The RAID numbers often get confusing
when
> > it comes to 1+0 or 0+1. One will be a stripe of mirrors and the other
is
> a
> > mirror of stripes. The difference is mainly in the redundancy as the
> stripe
> > of mirrors will tolerate potentially more failures than a mirror of
> stripes.
> > In either case all the disks are used but you only get half the usable
> disk
> > space. That is how Raid arrays work. You sacrifice drives for
redundancy
> > and speed. I don't know why you say you need to split your files. That
> > should not be necessary.
> >
> > --
> >
> > Andrew J. Kelly
> > SQL Server MVP
> >
> >
> > "Paul Cahill" <XYZpaul.cahillXYZ@.blueyonder.co.uk> wrote in message
> > news:eyHa3nY6DHA.2264@.tk2msftngp13.phx.gbl...
> > > A word of warning. I discovered my expensive Dell Perc3/DC controllers
> > > implement Raid 10 as a span (concatenation) of mirrors not a stripe.
> > > I have 22 disks and over half are idle.
> > > I'm having to split the database file and log file into pieces.
> > >
> > > Paul
> > >
> > >
> > > "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
> > > news:ucSRJy05DHA.2560@.TK2MSFTNGP09.phx.gbl...
> > > > But she can't do a RAID 10 with just 3 drives. It's either a Raid 1
> and
> > > you
> > > > loose a drive or Raid 5.
> > > >
> > > > --
> > > >
> > > > Andrew J. Kelly
> > > > SQL Server MVP
> > > >
> > > >
> > > > <sightdev@.yahoo.com> wrote in message
> > > > news:9861f5eb.0401300736.6761b95d@.posting.google.com...
> > > > > depends on your needs. If READ is the primary function, RAID5
makes
> > > > > sense because its less costly, but write is primary function
> > > > > RAID10(0+1) is the best solution.
> > > >
> > > >
> > >
> > >
> >
> >
>|||I am taking this up with Dell, others are discussing this in the Dell Talk
forum.
The sales guys and the 1st line tech support people don't even understand
the issue.
At the moment I'm getting unfufilled call back promises.
My main data file is on a (Dell) raid 10 of 6 disks 18GB disks. The main
data file is over 36GB. If I watch the lights on this logical array they do
all flash but not together. You can see it happening in pairs. If I/O on the
data file was truly random then I would be getting some bangs for all my
bucks but of course there are always hotspots in data access.
No single i/o will ever proceed faster than the speed of a single 18GB 15K
drive.
The only way I can see around this is to stripe using the perc3 and then
mirror the stripe using the operating system. Not a route I am prepared to
proceed with.
Paul
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
news:eImaq%23l6DHA.2480@.TK2MSFTNGP10.phx.gbl...
> Paul,
> I have to admit I don't know exactly what they are referring to.
Hopefully
> I can read more on it later but it doesn't sound pretty. I would call and
> talk to someone in tech support directly who says claims they know what
they
> are talking about when it comes to this implementation of RAID 10 to get
his
> take. If it's anything close to what the docs state I would ask for my
> money back since that is no where close to the definition of RAID 10 that
I
> have ever seen and I don't know how they can even claim it as such. From
> what I gather the reason why the other disks lights are not blinking is
that
> with "concatenation" it fills up the first disk before it moves to the
next
> and you probably don't have enough data on it yet. Hopefully we are just
> misreading their information but in either case I wish you luck.
>
>
> --
> Andrew J. Kelly
> SQL Server MVP
>
> "Paul Cahill" <XYZpaul.cahillXYZ@.blueyonder.co.uk> wrote in message
> news:OYmMKUj6DHA.1936@.TK2MSFTNGP12.phx.gbl...
> > You are correct on the raid levels and raid 10 is defined as a stripe of
> > mirrors. However Dell's documentation for the Perc3 and other
controllers
> > now states (and it's true) that their implementation of raid 10 is a
span
> of
> > mirrors. ie if you have a raid 10 of four 18GB disks and you create a
9GB
> > log file the file will wholy reside on the first mirror pair. The
second
> > mirror pair will not be used until the 1st mirror pair is full.
> >
> > This explains the dissappointing performance we have from our 22 disk
> > system. Although I benchmarked it, the one thing I did not do when I set
> it
> > up was to watch the disk lights.
> > For example our log file does indeed live on a 4 disk raid 10 array of
> 18GB
> > 15K drives. The log file is smaller than 18GB. When I/O occurs only two
of
> > the disk lights flash. The other two never flash. If it was true raid 10
> > then all 4 lights should flash as the i/o is striped.
> >
> > So I'm having to do the striping myself by spitting the files across
raid
> > arrays. ie Indexes on one, certain tables on another. Not a bad thing
> > anyway I guess. But if I'd known about dell's Raid 10 I'd have planned
> > differently. It's not east to make changes on a 24/7 system.
> >
> > An alternative with the dell perc3 would be to stripe the drives (Raid
0)
> > and then mirror using the O/S. Not one I care to choose.
> >
> > Paul
> >
> > http://docs.us.dell.com/docs/storage/perc3dc/ug/en/Levels.htm
> > The above document describes Raid 10 on the perc3/dc as a stripe of
> mirrors
> >
> >
> > http://docs.us.dell.com/docs/software/smarrman/marb32/ch8_perc.htm
> > This document shows that perc3/dc implements as a concatenation
> > Search for string "Supported RAID Levels for PERC Subsystem Controllers"
> >
> >
> >
http://docs.us.dell.com/docs/software/smarrman/marb32/ch3_stor.htm#1037893
> > This document describes spanned disks
> >
> >
> > "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
> > news:uXdx2uZ6DHA.2952@.TK2MSFTNGP09.phx.gbl...
> > > Paul,
> > >
> > > Not sure what you mean exactly. The RAID numbers often get confusing
> when
> > > it comes to 1+0 or 0+1. One will be a stripe of mirrors and the other
> is
> > a
> > > mirror of stripes. The difference is mainly in the redundancy as the
> > stripe
> > > of mirrors will tolerate potentially more failures than a mirror of
> > stripes.
> > > In either case all the disks are used but you only get half the usable
> > disk
> > > space. That is how Raid arrays work. You sacrifice drives for
> redundancy
> > > and speed. I don't know why you say you need to split your files.
That
> > > should not be necessary.
> > >
> > > --
> > >
> > > Andrew J. Kelly
> > > SQL Server MVP
> > >
> > >
> > > "Paul Cahill" <XYZpaul.cahillXYZ@.blueyonder.co.uk> wrote in message
> > > news:eyHa3nY6DHA.2264@.tk2msftngp13.phx.gbl...
> > > > A word of warning. I discovered my expensive Dell Perc3/DC
controllers
> > > > implement Raid 10 as a span (concatenation) of mirrors not a stripe.
> > > > I have 22 disks and over half are idle.
> > > > I'm having to split the database file and log file into pieces.
> > > >
> > > > Paul
> > > >
> > > >
> > > > "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
> > > > news:ucSRJy05DHA.2560@.TK2MSFTNGP09.phx.gbl...
> > > > > But she can't do a RAID 10 with just 3 drives. It's either a Raid
1
> > and
> > > > you
> > > > > loose a drive or Raid 5.
> > > > >
> > > > > --
> > > > >
> > > > > Andrew J. Kelly
> > > > > SQL Server MVP
> > > > >
> > > > >
> > > > > <sightdev@.yahoo.com> wrote in message
> > > > > news:9861f5eb.0401300736.6761b95d@.posting.google.com...
> > > > > > depends on your needs. If READ is the primary function, RAID5
> makes
> > > > > > sense because its less costly, but write is primary function
> > > > > > RAID10(0+1) is the best solution.
> > > > >
> > > > >
> > > >
> > > >
> > >
> > >
> >
> >
>
RAID 1 vs RAID 10
Which one is faster RAID 1 (on local disk drives) or RAID 10 (on a SAN)? We
are wondering what to use for the log files.RAID10 will be faster than RAID1 whether it's on the SAN or not. The SAN
should be faster than local disks, but that depends on what other systems
are also using the SAN.
"Shiva" <arbitsquare@.hotmail.com> wrote in message
news:Oj9AKs5cGHA.1208@.TK2MSFTNGP04.phx.gbl...
> Which one is faster RAID 1 (on local disk drives) or RAID 10 (on a SAN)?
> We are wondering what to use for the log files.
>|||> The SAN should be faster than local disks, but that depends on
> what other systems are also using the SAN.
SAN is not necessarily faster than local disks, and it doesn't depend on
what other systems are using the SAN. Whether you get better performance with
SAN or local disks depends on how they are configured.
Conceivably, you can >almost< always configure local disks to outperform
disks presented from SAN.
Linchi
"Michael D'Angelo" wrote:
> RAID10 will be faster than RAID1 whether it's on the SAN or not. The SAN
> should be faster than local disks, but that depends on what other systems
> are also using the SAN.
> "Shiva" <arbitsquare@.hotmail.com> wrote in message
> news:Oj9AKs5cGHA.1208@.TK2MSFTNGP04.phx.gbl...
> > Which one is faster RAID 1 (on local disk drives) or RAID 10 (on a SAN)?
> > We are wondering what to use for the log files.
> >
>
>|||This is a multi-part message in MIME format.
--000104000206050106050406
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Additionally, RAID 10 is typically only faster than RAID 1 in terms of
read performance. For writes, which transactions logs consist of nearly
100%, both are pretty close in performance. Also, since transaction
logs are sequential and the heads usually stay over the same spot on the
platters, you don't get the random I/O benefit that RAID 10 normally
gives with the striping. So a RAID 10 volume would, under most
circumstances, be no better than a RAID 1 volume for logs.
Kalen Delaney wrote a good section on RAID volumes in Inside SQL Server
2000 - worth a read. Also you can get some good ideas about disk
configuration from reading the data & log layout sections in the TCP-C
benchmark full disclosure reports on www.tcp.org (section 4.2
"Distribution of Tables and Logs" in the IBM full disclosure reports or
section 4.1 "Database Layout" in the HP full disclosure reports).
Microsoft used to use RAID1 for logs from memory but I noticed the most
recent one they had (SQL 2005 1.2M benchmark) used RAID1+0 physical and
then NT striping across those logical RAID volumes. The DB2 3.2M
benchmark and the Oracle's 1.6M benchmark both used RAID5+0 as far as I
can tell (DB2 - stripes across 10 separate RAID5 volumes, each volume
consisting of 14 spindles; Oracle - stripes across 8 RAID5 volumes, each
volume consisting of 12 spindles). So all the top benchmarks tend to
use striping of some sorts, which is interesting since for write
performance it shouldn't be any faster really than straight mirroring.
--
*mike hodgson*
http://sqlnerd.blogspot.com
Linchi Shea wrote:
>>The SAN should be faster than local disks, but that depends on
>>what other systems are also using the SAN.
>>
>SAN is not necessarily faster than local disks, and it doesn't depend on
>what other systems are using the SAN. Whether you get better performance with
>SAN or local disks depends on how they are configured.
>Conceivably, you can >almost< always configure local disks to outperform
>disks presented from SAN.
>Linchi
>"Michael D'Angelo" wrote:
>
>>RAID10 will be faster than RAID1 whether it's on the SAN or not. The SAN
>>should be faster than local disks, but that depends on what other systems
>>are also using the SAN.
>>"Shiva" <arbitsquare@.hotmail.com> wrote in message
>>news:Oj9AKs5cGHA.1208@.TK2MSFTNGP04.phx.gbl...
>>
>>Which one is faster RAID 1 (on local disk drives) or RAID 10 (on a SAN)?
>>We are wondering what to use for the log files.
>>
>>
>>
--000104000206050106050406
Content-Type: text/html; charset=UTF-8
Content-Transfer-Encoding: 8bit
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html;charset=UTF-8" http-equiv="Content-Type">
</head>
<body bgcolor="#ffffff" text="#000000">
<tt>Additionally, RAID 10 is typically only faster than RAID 1 in terms
of read performance. For writes, which transactions logs consist of
nearly 100%, both are pretty close in performance. Also, since
transaction logs are sequential and the heads usually stay over the
same spot on the platters, you don't get the random I/O benefit that
RAID 10 normally gives with the striping. So a RAID 10 volume would,
under most circumstances, be no better than a RAID 1 volume for logs.<br>
<br>
Kalen Delaney wrote a good section on RAID volumes in Inside SQL Server
2000 - worth a read. Also you can get some good ideas about disk
configuration from reading the data & log layout sections in the
TCP-C benchmark full disclosure reports on <a class="moz-txt-link-abbreviated" href="http://links.10026.com/?link=www.tcp.org</a>">http://www.tcp.org">www.tcp.org</a> (section 4.2
"Distribution of Tables and Logs" in the IBM full disclosure reports or
section 4.1 "Database Layout" in the HP full disclosure reports).Â
Microsoft used to use RAID1 for logs from memory but I noticed the most
recent one they had (SQL 2005 1.2M benchmark) used RAID1+0 physical and
then NT striping across those logical RAID volumes. The DB2 3.2M
benchmark and the </tt><tt>Oracle's 1.6M benchmark both </tt><tt>used
RAID5+0 as far as I can tell (DB2 - stripes across 10 separate RAID5
volumes, each volume consisting of 14 spindles; Oracle - stripes across
8 RAID5 volumes, each volume consisting of 12 spindles). So all the
top benchmarks tend to use striping of some sorts, which is interesting
since for write performance it shouldn't be any faster really than
straight mirroring.<br>
</tt>
<div class="moz-signature">
<title></title>
<meta http-equiv="Content-Type" content="text/html; ">
<p><span lang="en-au"><font face="Tahoma" size="2">--<br>
</font></span> <b><span lang="en-au"><font face="Tahoma" size="2">mike
hodgson</font></span></b><span lang="en-au"><br>
<font face="Tahoma" size="2"><a href="http://links.10026.com/?link=http://sqlnerd.blogspot.com</a></font></span>">http://sqlnerd.blogspot.com">http://sqlnerd.blogspot.com</a></font></span>
</p>
</div>
<br>
<br>
Linchi Shea wrote:
<blockquote cite="mid3EAE716E-B80B-41E8-86BD-53C672D67935@.microsoft.com"
type="cite">
<blockquote type="cite">
<pre wrap="">The SAN should be faster than local disks, but that depends on
what other systems are also using the SAN.
</pre>
</blockquote>
<pre wrap=""><!-->
SAN is not necessarily faster than local disks, and it doesn't depend on
what other systems are using the SAN. Whether you get better performance with
SAN or local disks depends on how they are configured.
Conceivably, you can >almost< always configure local disks to outperform
disks presented from SAN.
Linchi
"Michael D'Angelo" wrote:
</pre>
<blockquote type="cite">
<pre wrap="">RAID10 will be faster than RAID1 whether it's on the SAN or not. The SAN
should be faster than local disks, but that depends on what other systems
are also using the SAN.
"Shiva" <a class="moz-txt-link-rfc2396E" href="http://links.10026.com/?link=mailto:arbitsquare@.hotmail.com"><arbitsquare@.hotmail.com></a> wrote in message
<a class="moz-txt-link-freetext" href="http://links.10026.com/?link=news:Oj9AKs5cGHA.1208@.TK2MSFTNGP04.phx.gbl">news:Oj9AKs5cGHA.1208@.TK2MSFTNGP04.phx.gbl</a>...
</pre>
<blockquote type="cite">
<pre wrap="">Which one is faster RAID 1 (on local disk drives) or RAID 10 (on a SAN)?
We are wondering what to use for the log files.
</pre>
</blockquote>
<pre wrap="">
</pre>
</blockquote>
</blockquote>
</body>
</html>
--000104000206050106050406--|||"Linchi Shea" <LinchiShea@.discussions.microsoft.com> wrote in message
news:3EAE716E-B80B-41E8-86BD-53C672D67935@.microsoft.com...
>> The SAN should be faster than local disks, but that depends on
>> what other systems are also using the SAN.
> SAN is not necessarily faster than local disks, and it doesn't depend on
> what other systems are using the SAN. Whether you get better performance
> with
> SAN or local disks depends on how they are configured.
> Conceivably, you can >almost< always configure local disks to outperform
> disks presented from SAN.
> Linchi
I'd be interested to see when that would be the case. If both cases have
the same disk configuration, but your local raid controller has, say, 128mb
of cache, but the SAN has a 2gb cache, wouldn't the SAN conceivable
outperform local disk?
Of course I can see if local disks or the SAN can provide more physical
disks than the other, then that would make a difference.
> "Michael D'Angelo" wrote:
>> RAID10 will be faster than RAID1 whether it's on the SAN or not. The SAN
>> should be faster than local disks, but that depends on what other systems
>> are also using the SAN.
>> "Shiva" <arbitsquare@.hotmail.com> wrote in message
>> news:Oj9AKs5cGHA.1208@.TK2MSFTNGP04.phx.gbl...
>> > Which one is faster RAID 1 (on local disk drives) or RAID 10 (on a
>> > SAN)?
>> > We are wondering what to use for the log files.
>> >
>>|||This is a multi-part message in MIME format.
--050308030100090101020702
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
The most likely factor that would influence SAN disk performance would
be load applied by other hosts (mostly on the disks themselves, but also
the SAN cache & controllers). With the local disks they're always 100%
dedicated to the SQL host, but often (not always but often) the RAID
group on the SAN that you get your LUNs for SQL from will also be used
by other systems like email, other SQL hosts, file servers, VMs, etc.
Also, depending on how the cache on the SAN is configured it may not be
very useful for what SQL will use the LUN for (so that 2GB cache may be
useless). For example, if the cache is configured mostly for read, then
that's not going to help transaction log LUNs, which are almost
exclusively write only.
Most of the time I would think SAN LUNs ought to give better
performance, all things being equal, but I can see cases (and have
experienced them myself - sharing with Exchange can be a dog) where
local DAS disks can yield better performance.
--
*mike hodgson*
http://sqlnerd.blogspot.com
Michael D'Angelo wrote:
>"Linchi Shea" <LinchiShea@.discussions.microsoft.com> wrote in message
>news:3EAE716E-B80B-41E8-86BD-53C672D67935@.microsoft.com...
>
>>The SAN should be faster than local disks, but that depends on
>>what other systems are also using the SAN.
>>
>>SAN is not necessarily faster than local disks, and it doesn't depend on
>>what other systems are using the SAN. Whether you get better performance
>>with
>>SAN or local disks depends on how they are configured.
>>Conceivably, you can >almost< always configure local disks to outperform
>>disks presented from SAN.
>>Linchi
>>
>I'd be interested to see when that would be the case. If both cases have
>the same disk configuration, but your local raid controller has, say, 128mb
>of cache, but the SAN has a 2gb cache, wouldn't the SAN conceivable
>outperform local disk?
>Of course I can see if local disks or the SAN can provide more physical
>disks than the other, then that would make a difference.
>
>>"Michael D'Angelo" wrote:
>>
>>RAID10 will be faster than RAID1 whether it's on the SAN or not. The SAN
>>should be faster than local disks, but that depends on what other systems
>>are also using the SAN.
>>"Shiva" <arbitsquare@.hotmail.com> wrote in message
>>news:Oj9AKs5cGHA.1208@.TK2MSFTNGP04.phx.gbl...
>>
>>Which one is faster RAID 1 (on local disk drives) or RAID 10 (on a
>>SAN)?
>>We are wondering what to use for the log files.
>>
>>
>>
>
>
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<tt>The most likely factor that would influence SAN disk performance
would be load applied by other hosts (mostly on the disks themselves,
but also the SAN cache & controllers). With the local disks
they're always 100% dedicated to the SQL host, but often (not always
but often) the RAID group on the SAN that you get your LUNs for SQL
from will also be used by other systems like email, other SQL hosts,
file servers, VMs, etc.<br>
<br>
Also, depending on how the cache on the SAN is configured it may not be
very useful for what SQL will use the LUN for (so that 2GB cache may be
useless). For example, if the cache is configured mostly for read,
then that's not going to help transaction log LUNs, which are almost
exclusively write only.<br>
<br>
Most of the time I would think SAN LUNs ought to give better
performance, all things being equal, but I can see cases (and have
experienced them myself - sharing with Exchange can be a dog) where
local DAS disks can yield better performance.<br>
</tt>
<div class="moz-signature">
<title></title>
<meta http-equiv="Content-Type" content="text/html; ">
<p><span lang="en-au"><font face="Tahoma" size="2">--<br>
</font></span> <b><span lang="en-au"><font face="Tahoma" size="2">mike
hodgson</font></span></b><span lang="en-au"><br>
<font face="Tahoma" size="2"><a href="http://links.10026.com/?link=http://sqlnerd.blogspot.com</a></font></span>">http://sqlnerd.blogspot.com">http://sqlnerd.blogspot.com</a></font></span>
</p>
</div>
<br>
<br>
Michael D'Angelo wrote:
<blockquote cite="miduHUeVXHdGHA.1208@.TK2MSFTNGP02.phx.gbl" type="cite">
<pre wrap="">"Linchi Shea" <a class="moz-txt-link-rfc2396E" href="http://links.10026.com/?link=mailto:LinchiShea@.discussions.microsoft.com"><LinchiShea@.discussions.microsoft.com></a> wrote in message
<a class="moz-txt-link-freetext" href="http://links.10026.com/?link=news:3EAE716E-B80B-41E8-86BD-53C672D67935@.microsoft.com">news:3EAE716E-B80B-41E8-86BD-53C672D67935@.microsoft.com</a>...
</pre>
<blockquote type="cite">
<blockquote type="cite">
<pre wrap="">The SAN should be faster than local disks, but that depends on
what other systems are also using the SAN.
</pre>
</blockquote>
<pre wrap="">SAN is not necessarily faster than local disks, and it doesn't depend on
what other systems are using the SAN. Whether you get better performance
with
SAN or local disks depends on how they are configured.
Conceivably, you can >almost< always configure local disks to outperform
disks presented from SAN.
Linchi
</pre>
</blockquote>
<pre wrap=""><!-->
I'd be interested to see when that would be the case. If both cases have
the same disk configuration, but your local raid controller has, say, 128mb
of cache, but the SAN has a 2gb cache, wouldn't the SAN conceivable
outperform local disk?
Of course I can see if local disks or the SAN can provide more physical
disks than the other, then that would make a difference.
</pre>
<blockquote type="cite">
<pre wrap="">"Michael D'Angelo" wrote:
</pre>
<blockquote type="cite">
<pre wrap="">RAID10 will be faster than RAID1 whether it's on the SAN or not. The SAN
should be faster than local disks, but that depends on what other systems
are also using the SAN.
"Shiva" <a class="moz-txt-link-rfc2396E" href="http://links.10026.com/?link=mailto:arbitsquare@.hotmail.com"><arbitsquare@.hotmail.com></a> wrote in message
<a class="moz-txt-link-freetext" href="http://links.10026.com/?link=news:Oj9AKs5cGHA.1208@.TK2MSFTNGP04.phx.gbl">news:Oj9AKs5cGHA.1208@.TK2MSFTNGP04.phx.gbl</a>...
</pre>
<blockquote type="cite">
<pre wrap="">Which one is faster RAID 1 (on local disk drives) or RAID 10 (on a
SAN)?
We are wondering what to use for the log files.
</pre>
</blockquote>
<pre wrap="">
</pre>
</blockquote>
</blockquote>
<pre wrap=""><!-->
</pre>
</blockquote>
</body>
</html>
--050308030100090101020702--
are wondering what to use for the log files.RAID10 will be faster than RAID1 whether it's on the SAN or not. The SAN
should be faster than local disks, but that depends on what other systems
are also using the SAN.
"Shiva" <arbitsquare@.hotmail.com> wrote in message
news:Oj9AKs5cGHA.1208@.TK2MSFTNGP04.phx.gbl...
> Which one is faster RAID 1 (on local disk drives) or RAID 10 (on a SAN)?
> We are wondering what to use for the log files.
>|||> The SAN should be faster than local disks, but that depends on
> what other systems are also using the SAN.
SAN is not necessarily faster than local disks, and it doesn't depend on
what other systems are using the SAN. Whether you get better performance with
SAN or local disks depends on how they are configured.
Conceivably, you can >almost< always configure local disks to outperform
disks presented from SAN.
Linchi
"Michael D'Angelo" wrote:
> RAID10 will be faster than RAID1 whether it's on the SAN or not. The SAN
> should be faster than local disks, but that depends on what other systems
> are also using the SAN.
> "Shiva" <arbitsquare@.hotmail.com> wrote in message
> news:Oj9AKs5cGHA.1208@.TK2MSFTNGP04.phx.gbl...
> > Which one is faster RAID 1 (on local disk drives) or RAID 10 (on a SAN)?
> > We are wondering what to use for the log files.
> >
>
>|||This is a multi-part message in MIME format.
--000104000206050106050406
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Additionally, RAID 10 is typically only faster than RAID 1 in terms of
read performance. For writes, which transactions logs consist of nearly
100%, both are pretty close in performance. Also, since transaction
logs are sequential and the heads usually stay over the same spot on the
platters, you don't get the random I/O benefit that RAID 10 normally
gives with the striping. So a RAID 10 volume would, under most
circumstances, be no better than a RAID 1 volume for logs.
Kalen Delaney wrote a good section on RAID volumes in Inside SQL Server
2000 - worth a read. Also you can get some good ideas about disk
configuration from reading the data & log layout sections in the TCP-C
benchmark full disclosure reports on www.tcp.org (section 4.2
"Distribution of Tables and Logs" in the IBM full disclosure reports or
section 4.1 "Database Layout" in the HP full disclosure reports).
Microsoft used to use RAID1 for logs from memory but I noticed the most
recent one they had (SQL 2005 1.2M benchmark) used RAID1+0 physical and
then NT striping across those logical RAID volumes. The DB2 3.2M
benchmark and the Oracle's 1.6M benchmark both used RAID5+0 as far as I
can tell (DB2 - stripes across 10 separate RAID5 volumes, each volume
consisting of 14 spindles; Oracle - stripes across 8 RAID5 volumes, each
volume consisting of 12 spindles). So all the top benchmarks tend to
use striping of some sorts, which is interesting since for write
performance it shouldn't be any faster really than straight mirroring.
--
*mike hodgson*
http://sqlnerd.blogspot.com
Linchi Shea wrote:
>>The SAN should be faster than local disks, but that depends on
>>what other systems are also using the SAN.
>>
>SAN is not necessarily faster than local disks, and it doesn't depend on
>what other systems are using the SAN. Whether you get better performance with
>SAN or local disks depends on how they are configured.
>Conceivably, you can >almost< always configure local disks to outperform
>disks presented from SAN.
>Linchi
>"Michael D'Angelo" wrote:
>
>>RAID10 will be faster than RAID1 whether it's on the SAN or not. The SAN
>>should be faster than local disks, but that depends on what other systems
>>are also using the SAN.
>>"Shiva" <arbitsquare@.hotmail.com> wrote in message
>>news:Oj9AKs5cGHA.1208@.TK2MSFTNGP04.phx.gbl...
>>
>>Which one is faster RAID 1 (on local disk drives) or RAID 10 (on a SAN)?
>>We are wondering what to use for the log files.
>>
>>
>>
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<tt>Additionally, RAID 10 is typically only faster than RAID 1 in terms
of read performance. For writes, which transactions logs consist of
nearly 100%, both are pretty close in performance. Also, since
transaction logs are sequential and the heads usually stay over the
same spot on the platters, you don't get the random I/O benefit that
RAID 10 normally gives with the striping. So a RAID 10 volume would,
under most circumstances, be no better than a RAID 1 volume for logs.<br>
<br>
Kalen Delaney wrote a good section on RAID volumes in Inside SQL Server
2000 - worth a read. Also you can get some good ideas about disk
configuration from reading the data & log layout sections in the
TCP-C benchmark full disclosure reports on <a class="moz-txt-link-abbreviated" href="http://links.10026.com/?link=www.tcp.org</a>">http://www.tcp.org">www.tcp.org</a> (section 4.2
"Distribution of Tables and Logs" in the IBM full disclosure reports or
section 4.1 "Database Layout" in the HP full disclosure reports).Â
Microsoft used to use RAID1 for logs from memory but I noticed the most
recent one they had (SQL 2005 1.2M benchmark) used RAID1+0 physical and
then NT striping across those logical RAID volumes. The DB2 3.2M
benchmark and the </tt><tt>Oracle's 1.6M benchmark both </tt><tt>used
RAID5+0 as far as I can tell (DB2 - stripes across 10 separate RAID5
volumes, each volume consisting of 14 spindles; Oracle - stripes across
8 RAID5 volumes, each volume consisting of 12 spindles). So all the
top benchmarks tend to use striping of some sorts, which is interesting
since for write performance it shouldn't be any faster really than
straight mirroring.<br>
</tt>
<div class="moz-signature">
<title></title>
<meta http-equiv="Content-Type" content="text/html; ">
<p><span lang="en-au"><font face="Tahoma" size="2">--<br>
</font></span> <b><span lang="en-au"><font face="Tahoma" size="2">mike
hodgson</font></span></b><span lang="en-au"><br>
<font face="Tahoma" size="2"><a href="http://links.10026.com/?link=http://sqlnerd.blogspot.com</a></font></span>">http://sqlnerd.blogspot.com">http://sqlnerd.blogspot.com</a></font></span>
</p>
</div>
<br>
<br>
Linchi Shea wrote:
<blockquote cite="mid3EAE716E-B80B-41E8-86BD-53C672D67935@.microsoft.com"
type="cite">
<blockquote type="cite">
<pre wrap="">The SAN should be faster than local disks, but that depends on
what other systems are also using the SAN.
</pre>
</blockquote>
<pre wrap=""><!-->
SAN is not necessarily faster than local disks, and it doesn't depend on
what other systems are using the SAN. Whether you get better performance with
SAN or local disks depends on how they are configured.
Conceivably, you can >almost< always configure local disks to outperform
disks presented from SAN.
Linchi
"Michael D'Angelo" wrote:
</pre>
<blockquote type="cite">
<pre wrap="">RAID10 will be faster than RAID1 whether it's on the SAN or not. The SAN
should be faster than local disks, but that depends on what other systems
are also using the SAN.
"Shiva" <a class="moz-txt-link-rfc2396E" href="http://links.10026.com/?link=mailto:arbitsquare@.hotmail.com"><arbitsquare@.hotmail.com></a> wrote in message
<a class="moz-txt-link-freetext" href="http://links.10026.com/?link=news:Oj9AKs5cGHA.1208@.TK2MSFTNGP04.phx.gbl">news:Oj9AKs5cGHA.1208@.TK2MSFTNGP04.phx.gbl</a>...
</pre>
<blockquote type="cite">
<pre wrap="">Which one is faster RAID 1 (on local disk drives) or RAID 10 (on a SAN)?
We are wondering what to use for the log files.
</pre>
</blockquote>
<pre wrap="">
</pre>
</blockquote>
</blockquote>
</body>
</html>
--000104000206050106050406--|||"Linchi Shea" <LinchiShea@.discussions.microsoft.com> wrote in message
news:3EAE716E-B80B-41E8-86BD-53C672D67935@.microsoft.com...
>> The SAN should be faster than local disks, but that depends on
>> what other systems are also using the SAN.
> SAN is not necessarily faster than local disks, and it doesn't depend on
> what other systems are using the SAN. Whether you get better performance
> with
> SAN or local disks depends on how they are configured.
> Conceivably, you can >almost< always configure local disks to outperform
> disks presented from SAN.
> Linchi
I'd be interested to see when that would be the case. If both cases have
the same disk configuration, but your local raid controller has, say, 128mb
of cache, but the SAN has a 2gb cache, wouldn't the SAN conceivable
outperform local disk?
Of course I can see if local disks or the SAN can provide more physical
disks than the other, then that would make a difference.
> "Michael D'Angelo" wrote:
>> RAID10 will be faster than RAID1 whether it's on the SAN or not. The SAN
>> should be faster than local disks, but that depends on what other systems
>> are also using the SAN.
>> "Shiva" <arbitsquare@.hotmail.com> wrote in message
>> news:Oj9AKs5cGHA.1208@.TK2MSFTNGP04.phx.gbl...
>> > Which one is faster RAID 1 (on local disk drives) or RAID 10 (on a
>> > SAN)?
>> > We are wondering what to use for the log files.
>> >
>>|||This is a multi-part message in MIME format.
--050308030100090101020702
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
The most likely factor that would influence SAN disk performance would
be load applied by other hosts (mostly on the disks themselves, but also
the SAN cache & controllers). With the local disks they're always 100%
dedicated to the SQL host, but often (not always but often) the RAID
group on the SAN that you get your LUNs for SQL from will also be used
by other systems like email, other SQL hosts, file servers, VMs, etc.
Also, depending on how the cache on the SAN is configured it may not be
very useful for what SQL will use the LUN for (so that 2GB cache may be
useless). For example, if the cache is configured mostly for read, then
that's not going to help transaction log LUNs, which are almost
exclusively write only.
Most of the time I would think SAN LUNs ought to give better
performance, all things being equal, but I can see cases (and have
experienced them myself - sharing with Exchange can be a dog) where
local DAS disks can yield better performance.
--
*mike hodgson*
http://sqlnerd.blogspot.com
Michael D'Angelo wrote:
>"Linchi Shea" <LinchiShea@.discussions.microsoft.com> wrote in message
>news:3EAE716E-B80B-41E8-86BD-53C672D67935@.microsoft.com...
>
>>The SAN should be faster than local disks, but that depends on
>>what other systems are also using the SAN.
>>
>>SAN is not necessarily faster than local disks, and it doesn't depend on
>>what other systems are using the SAN. Whether you get better performance
>>with
>>SAN or local disks depends on how they are configured.
>>Conceivably, you can >almost< always configure local disks to outperform
>>disks presented from SAN.
>>Linchi
>>
>I'd be interested to see when that would be the case. If both cases have
>the same disk configuration, but your local raid controller has, say, 128mb
>of cache, but the SAN has a 2gb cache, wouldn't the SAN conceivable
>outperform local disk?
>Of course I can see if local disks or the SAN can provide more physical
>disks than the other, then that would make a difference.
>
>>"Michael D'Angelo" wrote:
>>
>>RAID10 will be faster than RAID1 whether it's on the SAN or not. The SAN
>>should be faster than local disks, but that depends on what other systems
>>are also using the SAN.
>>"Shiva" <arbitsquare@.hotmail.com> wrote in message
>>news:Oj9AKs5cGHA.1208@.TK2MSFTNGP04.phx.gbl...
>>
>>Which one is faster RAID 1 (on local disk drives) or RAID 10 (on a
>>SAN)?
>>We are wondering what to use for the log files.
>>
>>
>>
>
>
--050308030100090101020702
Content-Type: text/html; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<head>
<meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
</head>
<body bgcolor="#ffffff" text="#000000">
<tt>The most likely factor that would influence SAN disk performance
would be load applied by other hosts (mostly on the disks themselves,
but also the SAN cache & controllers). With the local disks
they're always 100% dedicated to the SQL host, but often (not always
but often) the RAID group on the SAN that you get your LUNs for SQL
from will also be used by other systems like email, other SQL hosts,
file servers, VMs, etc.<br>
<br>
Also, depending on how the cache on the SAN is configured it may not be
very useful for what SQL will use the LUN for (so that 2GB cache may be
useless). For example, if the cache is configured mostly for read,
then that's not going to help transaction log LUNs, which are almost
exclusively write only.<br>
<br>
Most of the time I would think SAN LUNs ought to give better
performance, all things being equal, but I can see cases (and have
experienced them myself - sharing with Exchange can be a dog) where
local DAS disks can yield better performance.<br>
</tt>
<div class="moz-signature">
<title></title>
<meta http-equiv="Content-Type" content="text/html; ">
<p><span lang="en-au"><font face="Tahoma" size="2">--<br>
</font></span> <b><span lang="en-au"><font face="Tahoma" size="2">mike
hodgson</font></span></b><span lang="en-au"><br>
<font face="Tahoma" size="2"><a href="http://links.10026.com/?link=http://sqlnerd.blogspot.com</a></font></span>">http://sqlnerd.blogspot.com">http://sqlnerd.blogspot.com</a></font></span>
</p>
</div>
<br>
<br>
Michael D'Angelo wrote:
<blockquote cite="miduHUeVXHdGHA.1208@.TK2MSFTNGP02.phx.gbl" type="cite">
<pre wrap="">"Linchi Shea" <a class="moz-txt-link-rfc2396E" href="http://links.10026.com/?link=mailto:LinchiShea@.discussions.microsoft.com"><LinchiShea@.discussions.microsoft.com></a> wrote in message
<a class="moz-txt-link-freetext" href="http://links.10026.com/?link=news:3EAE716E-B80B-41E8-86BD-53C672D67935@.microsoft.com">news:3EAE716E-B80B-41E8-86BD-53C672D67935@.microsoft.com</a>...
</pre>
<blockquote type="cite">
<blockquote type="cite">
<pre wrap="">The SAN should be faster than local disks, but that depends on
what other systems are also using the SAN.
</pre>
</blockquote>
<pre wrap="">SAN is not necessarily faster than local disks, and it doesn't depend on
what other systems are using the SAN. Whether you get better performance
with
SAN or local disks depends on how they are configured.
Conceivably, you can >almost< always configure local disks to outperform
disks presented from SAN.
Linchi
</pre>
</blockquote>
<pre wrap=""><!-->
I'd be interested to see when that would be the case. If both cases have
the same disk configuration, but your local raid controller has, say, 128mb
of cache, but the SAN has a 2gb cache, wouldn't the SAN conceivable
outperform local disk?
Of course I can see if local disks or the SAN can provide more physical
disks than the other, then that would make a difference.
</pre>
<blockquote type="cite">
<pre wrap="">"Michael D'Angelo" wrote:
</pre>
<blockquote type="cite">
<pre wrap="">RAID10 will be faster than RAID1 whether it's on the SAN or not. The SAN
should be faster than local disks, but that depends on what other systems
are also using the SAN.
"Shiva" <a class="moz-txt-link-rfc2396E" href="http://links.10026.com/?link=mailto:arbitsquare@.hotmail.com"><arbitsquare@.hotmail.com></a> wrote in message
<a class="moz-txt-link-freetext" href="http://links.10026.com/?link=news:Oj9AKs5cGHA.1208@.TK2MSFTNGP04.phx.gbl">news:Oj9AKs5cGHA.1208@.TK2MSFTNGP04.phx.gbl</a>...
</pre>
<blockquote type="cite">
<pre wrap="">Which one is faster RAID 1 (on local disk drives) or RAID 10 (on a
SAN)?
We are wondering what to use for the log files.
</pre>
</blockquote>
<pre wrap="">
</pre>
</blockquote>
</blockquote>
<pre wrap=""><!-->
</pre>
</blockquote>
</body>
</html>
--050308030100090101020702--
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