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@xxxxxxxxx EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)
