Raid 1+0 Configuration (0+1?)

I'm a relative newcomer to harddisk configurations, so bear with me. I
just have some questions about the way Raid 1+0 works. It's a
possibility that what I really want is Raid 0+1, but we'll figure that
out.
The way I understand that Raid 1+0 works is that you can have several
Raid 1 pairs joined together in a Raid 0 array. It looks like this:
Disk Disk Disk Disk
| | | |
R1 - R0 - R1 - R0 - R1 - R0 - R1
| | | |
Disk Disk Disk Disk
I have a few questions about this. The first question I have is: What
does this look like to Windows? I'm hoping that it appears as one
large volume that I can partition as I please. What I'd really like is
a logical configuration of 3 drives using the 4 disks: 1 drive for the
OS, 1 drive for the log files, and 1 drive for the data files. The
data drive would use 2 disks. Something like this:
C: D: E:
| |--| |
Disk Disk Disk Disk
| | | |
R1 - R0 - R1 - R0 - R1 - R0 - R1
| | | |
Disk Disk Disk Disk
Is this do-able from a Raid 1+0 configuration? Or do I need a Raid 0+1
configuration like this:
C: D: E:
| |--| |
Disk - R0 - Disk - R0 - Disk - R0 - Disk
|--|--|
R1
|--|--|
Disk - R0 - Disk - R0 - Disk - R0 - Disk
Also, what happens when a drive fails in the 1+0 array? Do reads and
writes still continue with the redundant drive, so that everything is
transparent to the user? When the drive is replaced, is there a huge
performance hit when the drive is being rebuilt?
Thanks in advance for all replies!
-EtanKeep in mind that if you have one large RAID array it will remain one large
raid array to Windows. You do not receive any benefit in partitioning the
one large array (other than the logical breakdown of where things are).
If you had one RAID array that you could use for the OS
and one RAID array that you could use for tempdb
and one RAID array that that you could use for the data files
and one RAID array that you could use for the log files
You might get better performance over one large raid array because the
different controllers and disks within each array could be doing different
things at the same time.
Keith
"Etan" <aaawalrus@.yahoo.com> wrote in message
news:1106070523.937785.276140@.z14g2000cwz.googlegroups.com...
> I'm a relative newcomer to harddisk configurations, so bear with me. I
> just have some questions about the way Raid 1+0 works. It's a
> possibility that what I really want is Raid 0+1, but we'll figure that
> out.
> The way I understand that Raid 1+0 works is that you can have several
> Raid 1 pairs joined together in a Raid 0 array. It looks like this:
> Disk Disk Disk Disk
> | | | |
> R1 - R0 - R1 - R0 - R1 - R0 - R1
> | | | |
> Disk Disk Disk Disk
> I have a few questions about this. The first question I have is: What
> does this look like to Windows? I'm hoping that it appears as one
> large volume that I can partition as I please. What I'd really like is
> a logical configuration of 3 drives using the 4 disks: 1 drive for the
> OS, 1 drive for the log files, and 1 drive for the data files. The
> data drive would use 2 disks. Something like this:
> C: D: E:
> | |--| |
> Disk Disk Disk Disk
> | | | |
> R1 - R0 - R1 - R0 - R1 - R0 - R1
> | | | |
> Disk Disk Disk Disk
>
> Is this do-able from a Raid 1+0 configuration? Or do I need a Raid 0+1
> configuration like this:
> C: D: E:
> | |--| |
> Disk - R0 - Disk - R0 - Disk - R0 - Disk
> |--|--|
> R1
> |--|--|
> Disk - R0 - Disk - R0 - Disk - R0 - Disk
>
> Also, what happens when a drive fails in the 1+0 array? Do reads and
> writes still continue with the redundant drive, so that everything is
> transparent to the user? When the drive is replaced, is there a huge
> performance hit when the drive is being rebuilt?
> Thanks in advance for all replies!
> -Etan
>|||I agree with Keith in that there is little to no benefit to having multiple
logical drives aon a single drive array. You can accomplish the same thing
by simply placing each of those type files in their own folder. If you
partition the array 3 ways you run the risk of running out of space on
logical drive and having too much on another. There is no performance
benefit to doing what you stated and it gives the false impression that the
files may be on different physical drives.
Andrew J. Kelly SQL MVP
"Keith Kratochvil" <sqlguy.back2u@.comcast.net> wrote in message
news:OKxHv5Y$EHA.2552@.TK2MSFTNGP09.phx.gbl...
> Keep in mind that if you have one large RAID array it will remain one
> large
> raid array to Windows. You do not receive any benefit in partitioning the
> one large array (other than the logical breakdown of where things are).
> If you had one RAID array that you could use for the OS
> and one RAID array that you could use for tempdb
> and one RAID array that that you could use for the data files
> and one RAID array that you could use for the log files
> You might get better performance over one large raid array because the
> different controllers and disks within each array could be doing different
> things at the same time.
> --
> Keith
>
> "Etan" <aaawalrus@.yahoo.com> wrote in message
> news:1106070523.937785.276140@.z14g2000cwz.googlegroups.com...
>