disk performance benchmarks

Hi,

I've been trying to spec a new server for my company's database for a
few weeks and one of the biggest problems I've had is trying to find
meaningful performance information about how PostgreSQL will perfom
under various disk configurations.

But, we have now taken the plunge and I'm in a position to do some
benchmarking to actually get some data.  Basically I was wondering if
anyone else had any particular recommendations (or requests) about the
most useful kinds of benchmarks to do.


The hardware I'll be benchmarking on is...

server 1:  single 2.8Ghz Xeon, 2Gb RAM.  Adaptec 2410SA SATA hardware
RAID, with 4 x 200Gb 7200rpm WD SATA drives.  RAID in both RAID5 and
RAID10 (currently RAID5, but want to experiment with write performance
in RAID10). Gentoo Linux

server 2: single 2.6Ghz Xeon, 2Gb RAM, single 80Gb IDE drive. Redhat
Linux

server 3: dual 2.6Ghz Xeon, 6Gb RAM, software RAID10 with 4 x 36Gb
10kRPM U320 SCSI drives, RedHat Linux


I realise the boxes aren't all identical - but some benchmarks on those
should give some ballpark figures for anyone else speccing out a
low-mid range box and wanting some performance figures on IDE vs IDE
RAID vs SCSI RAID

I'd be more than happy to post any results back to the list, and if
anyone else can contribute any other data points that'd be great.

Otherwise, any pointers to a quick/easy setup for some vaguely useful
benchmarks would be great.  At the moment I'm thinking just along the
lines of 'pgbench -c 10 -s 100 -v'.

Cheers

Shane