Bo,
> 2 - 2.4 Ghz Xeon processors
> 4GB ram
> 4 36gb 10000rpm scsi drives configured for raid 10
Hopefully you've turned OFF hyperthreading?
> gains can I expect on average from swapping from 4 disk raid 10 to 14 disk
> raid 10? Could I expect to see 40 - 50% better throughput.
This is so dependant on application design that I can't possibly estimate.
One big gain area for you will be moving the database log (pg_xlog) to its
own private disk resource (such as a raid-1 pair). In high-write
enviroments, this can gain you 15% without changing anything else.
> The servers listed above are the dell 2650's which have perc 3
> controllers. I have seen on this list where they are know for not
> performing well. So any suggestions for an attached scsi device would be
> greatly appreciated. Also, any thoughts on fibre channel storage devices?
The 2650s don't perform well in a whole assortment of ways. This is why they
are cheap.
NetApps seem to be the current best in NAS/SAN storage, although many people
like EMC. Stay away from Apple's XRaid, which is not designed for
databases.
--
--Josh
Josh Berkus
Aglio Database Solutions
San Francisco
