RIchard,
> its a dual xeon 2.4, 4gb ram and 3x identical 15k rpm scsi disks
>
> should i mirror 2 of the disks for postgres data, and use the 3rd disk for
the
> o/s and the pg logs or raid5 the 3 disks or even stripe 2 disks for pg and
> use the 3rd for o/s,logs,backups ?
I'd mirror 2. Stripey RAID with few disks imposes a heavy performance
penalty on data writes (particularly updates), sometimes as much as 50% for a
RAID5-3disk config.
I am a little curious why you've got a dual-xeon, but could only afford 3
disks ....
--
-Josh Berkus
Aglio Database Solutions
San Francisco
