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)
