Don't ever have WAL and data on the same OS volume as ext3. If data=writeback, performance will be fine, data integrity will be ok for WAL, but data integrity will not be sufficient for the data partition. If data=ordered, performance will be very bad, but data integrity will be OK. This is because an fsync on ext3 flushes _all dirty pages in the file system_ to disk, not just those for the file being fsync'd. One partition for WAL, one for data. If using ext3 this is essentially a performance requirement no matter how your array is set up underneath. On Aug 13, 2010, at 11:41 AM, Greg Smith wrote: > Bruce Momjian wrote: >> We recomment 'data=writeback' for ext3 in our docs >> > > Only for the WAL though, which is fine, and I think spelled out clearly > enough in the doc section you quoted. Ken's system has one big RAID > volume, which means he'd be mounting the data files with 'writeback' > too; that's the thing to avoid. > > -- > Greg Smith 2ndQuadrant US Baltimore, MD > PostgreSQL Training, Services and Support > greg@xxxxxxxxxxxxxxx www.2ndQuadrant.us > > > -- > Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-performance -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
