Hi,
As a gauge, we recently purchased several servers as our systems get
close to going operational. We bought Dell 2900s, with the cheapest quad
core processors (dual) and put most of the expense into lots of drives
(8 15K 146GB SAS drives in a RAID 10 set), and the PERC 6 embedded
controller with 512MB battery backed cache. That gives us more spindles,
the RAID redundancy we want, plus the high, reliable throughput of the
BBC. The OS (and probably WAL) will run on a RAID 1 pair of 15K 76GB
drives. We also went with 8GB memory, which seemed to be the price cost
point in these systems (going above 8GB had a much higher cost).
Besides, in our prototyping, or systems had 2GB, which we rarely
exceeded, so 8GB should be plently (and we can always expand).
So really, if you can save money on processors by going Opteron (and
your IT department doesn't have an Intel-based system requirement like
ours), put what you save into a good disk I/O subsystem. Hope that
helps.
Doug
-----Original Message-----
From: pgsql-performance-owner@postgresql.org
[mailto:pgsql-performance-owner@postgresql.org] On Behalf Of Adam Tauno
Williams
Sent: Friday, May 23, 2008 8:22 AM
To: pgsql-performance
Subject: Re: [PERFORM] Quad Xeon or Quad Opteron?
> Also, based on what I've seen on this list rather than personal
> experience, you might want to give more thought to your storage than
to
> CPU power. The usual thrust of advice seems to be: Get a fast, battery
> backed RAID controller. "Fast" does not mean "fast sequential I/O in
> ideal conditions so marketing can print a big number on the box"; you
> need to consider random I/O too. Get lots of fast disks. Get enough
RAM
> to ensure that your indexes fit in RAM if possible.
> Note, however, that I have no direct experience with big Pg databases;
> I'm just trying to provide you with a guide of what information to
> provide and what to think about so you can get better answers here
from
> people who actually have a clue.
Yep, we've had PostreSQL databases for a long time. The various
current generation processors, IMO, have no substantive difference in
practice; at least not relative to the bang-for-the-buck or more RAM
and good I/O.
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