Hi Steven, On Wed, Mar 18, 2015 at 12:21 PM, Steven Jones <steven.jones1201@xxxxxxxxxxx> wrote: > - system is HP blade; 128Gb RAM, 2x 8-core, 12x 10k RPM RAID1+0 (database) Have you BBU on your controller? And how your controller configured, I mean cache mode, io mode, disk write cache mode. You have 15K SAS (which form factor?) under WAL and 10K SAS under database, am I correct? > Full iostat/iotop, configuration, checkpoint stats, etc. are pasted below > for completeness. Highlights are: > checkpoint_segments=512 > shared_buffers=16GB > checkpoint_timeout=15min > checkpoint_completion_target=0.1 It looks like your checkpoint settings are a bit strange besides of everything else. If you chose high value for checkpoint_segments, your aim is to avoid checkpoints by timeout (or vice verse). If you have checkpoint_segments=512, your checkpoint_timeout should be about 60min. And anyway - checkpoint_completion_target=0.9 or 0.7 in order to spread disk load between checkpoints. > --- > sysctl settings for dirty pages > > vm.dirty_background_bytes = 0 > vm.dirty_background_ratio = 5 > vm.dirty_bytes = 0 > vm.dirty_expire_centisecs = 3000 > vm.dirty_ratio = 10 > vm.dirty_writeback_centisecs = 500 Values for this settings are really dependent of RAID (and BBU size). And about further problem description: have you any graphical representation of your % disc utilization? Best regards, Ilya -- Ilya Kosmodemiansky, PostgreSQL-Consulting.com tel. +14084142500 cell. +4915144336040 ik@xxxxxxxxxxxxxxxxxxxxxxxxx -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
