raid question

Hi,
I have 2 user databases and would like to know aouut the
configuration. I have read about RAID and intend to use
raid 1 for the logs and raid 5 for the databases. However,
(1) what is the ideal RAID level for tempdb?
(2) Also, when people talk about raid 5, do they use raid
5 for each database - eg 3 disks for master, 3 for msdb, 3
for each user database - or is it 3 disks for raid 5 and
all databases are placed on it?
(3) And the same question for the logs - presumably each
database has its own raid1 pair of disks?
TIA,
JB
JB,

> I have 2 user databases and would like to know aouut the
> configuration. I have read about RAID and intend to use
> raid 1 for the logs and raid 5 for the databases. However,
> (1) what is the ideal RAID level for tempdb?
RAID 1 - you will get some boost if tempdb can get its own raid array.
If you cannot do that, then put its data and log files with the other data
and log files.

> (2) Also, when people talk about raid 5, do they use raid
> 5 for each database - eg 3 disks for master, 3 for msdb, 3
> for each user database - or is it 3 disks for raid 5 and
> all databases are placed on it?
All the databases on the same RAID array, unless you have really serious
I/O issues and the money to spend. (If you have two databases, it is
unlikely that you have that big an issue.)

> (3) And the same question for the logs - presumably each
> database has its own raid1 pair of disks?
Almost never, as above. All logs on one raid array.
Russell Fields

> TIA,
> JB
|||Thanks Russell for the reply,
you mention that typically all logs are on the same raid
1 pair. I was thinking that the disk head not being where
it need to be to do the next write would mean that
performance would degrade in this case? Is there much
difference in your experience/opinion between one raid
pair per log or one pair for everything?
TIA,
JB
|||Few people have the luxury of having a separate Raid 1 for each log file
when they have multiple databases. It is better to share a Raid 1 with
other log files than data files. Unless you are constantly doing hundreds
or thousands of transactions per second a Raid 1 with several log files
should do fine.
Andrew J. Kelly SQL MVP
"JB" <anonymous@.discussions.microsoft.com> wrote in message
news:623a01c492a3$0ef79e50$a301280a@.phx.gbl...
> Thanks Russell for the reply,
> you mention that typically all logs are on the same raid
> 1 pair. I was thinking that the disk head not being where
> it need to be to do the next write would mean that
> performance would degrade in this case? Is there much
> difference in your experience/opinion between one raid
> pair per log or one pair for everything?
> TIA,
> JB
>
|||Also most folks have a single raid 5 array for all of their user database.
Wayne Snyder, MCDBA, SQL Server MVP
Mariner, Charlotte, NC
www.mariner-usa.com
(Please respond only to the newsgroups.)
I support the Professional Association of SQL Server (PASS) and it's
community of SQL Server professionals.
www.sqlpass.org
"JB" <anonymous@.discussions.microsoft.com> wrote in message
news:5f9001c4928b$ce1ef020$a601280a@.phx.gbl...
> Hi,
> I have 2 user databases and would like to know aouut the
> configuration. I have read about RAID and intend to use
> raid 1 for the logs and raid 5 for the databases. However,
> (1) what is the ideal RAID level for tempdb?
> (2) Also, when people talk about raid 5, do they use raid
> 5 for each database - eg 3 disks for master, 3 for msdb, 3
> for each user database - or is it 3 disks for raid 5 and
> all databases are placed on it?
> (3) And the same question for the logs - presumably each
> database has its own raid1 pair of disks?
> TIA,
> JB
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