Re: choosing the right RAID level for PostgresQL database

On Sun, Feb 13, 2011 at 1:12 PM, sergey <sergey(dot)on(dot)net(at)gmail(dot)com> wrote:
> Hello,
>
> I got a disk array appliance of 8 disks 1T each (UltraStor RS8IP4). It will
> be used solely by PostgresQL database and I am trying to choose the best
> RAID level for it.
>
> The most priority is for read performance since we operate large data sets
> (tables, indexes) and we do lots of searches/scans, joins and nested
> queries. With the old disks that we have now the most slowdowns happen on
> SELECTs.
>
> Fault tolerance is less important, it can be 1 or 2 disks.
>
> Space is the least important factor. Even 1T will be enough.
>
> Which RAID level would you recommend in this situation. The current options
> are 60, 50 and 10, but probably other options can be even better.

Unless testing shows some other level is better, RAID-10 is usually
the best. with software RAID-10 and 24 disks I can flood a 4 channel
SAS cable with sequential transfers quite easily, and for random
access it's very good as well, allowing me to reach about 5 to 6k tps
with a large pgbench db (-i -s 4000) ~ 40Gig