Re: Ideal Hardware?

Josh Berkus <josh@agliodbs.com>

From: Josh Berkus <josh@agliodbs.com>
To: <ghaverla@freenet.edmonton.ab.ca>, Jason Hihn <jhihn@paytimepayroll.com>
Cc: "Pgsql-Novice@Postgresql. Org" <pgsql-novice@postgresql.org>
Date: 2003-10-02T01:10:31Z
Lists: pgsql-performance, pgsql-novice
Gord,

> I vaguely remember someone (Tom?) mentioning that one of the log
> files probably might want to go on its own partition. 

That's general knowledge, but not really applicable to a fast RAID system.   
It's more imporant to regular-disk systems; with 4+ disk RAID, nobody has 
been able to demonstrate a gain from having the disk separation.

> fast, rebuilding RAID 1 is a pain in the butt!  My biggest RAID 10
> is about 10 GB, bundling the new partition from the new disk into
> the RAID 0 is fast, rebuilding the mirror (RAID 1 part) takes 10
> hours!  Dual athlon 1.6's and 1 GB of RAM, so I have lots of
> horsepower.  Maybe you are going with better RAID than I have,
> but it seems to me that RAID 5 (with spares) is going to be better
> if you ever have to rebuild.

Also depends on the number of disks, the controller, and the balance of read 
vs. write activity.   I've found RAID 5 with no cache to be dog-slow for OLTP 
(heavy write transaction) databases, and use RAID 1 for that.

-- 
-Josh Berkus
 Aglio Database Solutions
 San Francisco