On Sun, 6 Jul 2008, Jaime Casanova wrote:
Here http://www.westnet.com/~gsmith/content/postgresql/TuningPGWAL.htm I read: """ Combining these two, an optimal fstab for the WAL might look like this: /dev/hda2 /var ext3 defaults,writeback,noatime 1 2 """ Is this info accurate?
Nah, that guy doesn't know what he's talking about. That article is overdue for an overhaul.
I also read on other document from the "technical documentation" that for partitions where you have the tables and indexes is better to have journaling and for partitions for the WAL is better to not have journalling...
The WAL is itself a sort of journal, and the way writes to it are done the filesystem level journaling that ext3 provides doesn't buy you much beyond additional overhead. Check out http://www.commandprompt.com/blogs/joshua_drake/2008/04/is_that_performance_i_smell_ext2_vs_ext3_on_50_spindles_testing_for_postgresql/ for an extensive comparison of different options here, where you can see that using ext2 instead can be much more efficient. The main downside of ext2 is that you might get longer boot times from running fsck, but it won't be any less reliable for database use though.
-- * Greg Smith gsmith@xxxxxxxxxxxxx http://www.gregsmith.com Baltimore, MD
