Re: RAID 10 or RAID 10 + RAID 1

On Tue, Aug 14, 2007 at 01:14:39PM +0300, Michael Ben-Nes wrote:
> Hello,
>
> I need to setup a web server with PostgreSQL. The heaviest application will
> be product comparisons engine that will analyze 5-10 Million products.
>
> I have 6 SAS 15K disks, how should I set them up:
>
> RAID 10 on all 6 disks ( OS + Apache + PostgreSQL )
> RAID 1 on 2 disks ( OS + Apache ) + RAID 10 on 4 disks ( PostgreSQL )

If the controller is any good and has a battery-backed write cache,
you'll probably do better with a 6 disk RAID10. If not, I'd put all the
data on a 4 disk RAID10, and everything else (including pg_xlog!) on a
mirror.

> What is the recommended stripe size ( The computer is Dell PowerEdge 2950 )

If you search through the archives I think you'll find some stuff about
stripe size and performance.

As always, your best bet is to benchmark both approaches with your
actual application.
--
Decibel!, aka Jim Nasby                        decibel@decibel.org
EnterpriseDB      http://enterprisedb.com      512.569.9461 (cell)