Re: best arrangement of 3 disks for (insert) performance

The dual xeon arrangement is because the machine will also have to do some
collaborative filtering which is very cpu intensive and very disk
un-intensive, after loading the data into ram.

On Friday 12 September 2003 5:49 pm, you wrote:
> 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 ....