On Thu, Aug 4, 2011 at 6:41 AM, Nicholson, Brad (Toronto, ON, CA) <bnichol...@hp.com> wrote: >> -----Original Message----- >> From: pgsql-performance-ow...@postgresql.org [mailto:pgsql-performance- >> ow...@postgresql.org] On Behalf Of Scott Marlowe >> Sent: Thursday, August 04, 2011 4:46 AM >> To: Willy-Bas Loos >> Cc: Adarsh Sharma; pgsql-performance@postgresql.org >> Subject: Re: [PERFORM] Need to tune for Heavy Write >> >> >> > Moving the pg_xlog to a different directory only helps when that >> > directory is on a different harddisk (or whatever I/O device). >> >> Not entirely true. By simply being on a different mounted file >> system this moves the fsync calls on the pg_xlog directories off of >> the same file system as the main data store. Previous testing has >> shown improvements in performance from just using a different file >> system. >> > > Is this still the case for xfs or ext4 where fsync is properly flushing only > the correct blocks to disk, or was this referring to the good old ext3 flush > everything on fysnc issue?
Good question. One I do not know the answer to. Since I run my dbs with separate pg_xlog drive sets I've never been able to test that. -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
