From: Jim C. Nasby <jim@nasby.net>
To: Jeff Frost <jeff@frostconsultingllc.com>
Cc: Alvaro Herrera <alvherre@commandprompt.com>
Cc: Ron <rjpeace@earthlink.net>
Cc: Guy Rouillier <guyr-ml1@burntmail.com>
Cc: PostgreSQL Performance <pgsql-performance@postgresql.org>
Subject: Re: High update activity, PostgreSQL vs BigDBMS
Date: Tue, 9 Jan 2007 06:33:15 -0600
Message-ID: <20070109123312.GL12217@nasby.net> (raw)
In-Reply-To: <Pine.LNX.4.64.0612281410420.16866@discord.home.frostconsultingllc.com>
References: <45935A49.6080602@burntmail.com>
<E1H0HFH-0004cw-6E@elasmtp-dupuy.atl.sa.earthlink.net>
<20061229220747.GB15429@alvh.no-ip.org>
<Pine.LNX.4.64.0612281410420.16866@discord.home.frostconsultingllc.com>
On Thu, Dec 28, 2006 at 02:15:31PM -0800, Jeff Frost wrote:
> When benchmarking various options for a new PG server at one of my clients,
> I tried ext2 and ext3 (data=writeback) for the WAL and it appeared to be
> fastest to have ext2 for the WAL. The winning time was 157m46.713s for
> ext2, 159m47.098s for combined ext3 data/xlog and 158m25.822s for ext3
> data=writeback. This was on an 8x150GB Raptor RAID10 on an Areca 1130 w/
> 1GB BBU cache. This config benched out faster than a 6disk RAID10 + 2 disk
> RAID1 for those of you who have been wondering if the BBU write back cache
> mitigates the need for separate WAL (at least on this workload). Those are
> the fastest times for each config, but ext2 WAL was always faster than the
> other two options. I didn't test any other filesystems in this go around.
Uh, if I'm reading this correctly, you're saying that WAL on a separate
ext2 vs. one big ext3 with data=writeback saved ~39 seconds out of
~158.5 minutes, or 0.4%? Is that even above the noise for your
measurements? I suspect the phase of the moon might play a bigger role
;P
--
Jim Nasby jim@nasby.net
EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: jim@nasby.net, jeff@frostconsultingllc.com, alvherre@commandprompt.com, rjpeace@earthlink.net, guyr-ml1@burntmail.com
Subject: Re: High update activity, PostgreSQL vs BigDBMS
In-Reply-To: <20070109123312.GL12217@nasby.net>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox