On Mon, Feb 18, 2013 at 6:39 PM, Josh Berkus <josh@xxxxxxxxxxxx> wrote: > Scott, > >> So do you have generally slow IO, or is it fsync behavior etc? > > All tests except pgBench show this system as superfast. Bonnie++ and DD > tests are good (200 to 300mb/s), and test_fsync shows 14K/second. > Basically it has no issues until checkpoint kicks in, at which time the > entire system basically halts for the duration of the checkpoint. > > For that matter, if I run a pgbench and halt it just before checkpoint > kicks in, I get around 12000TPS, which is what I'd expect on this system. > > At this point, we've tried 3.2.0.26, 3.2.0.27, 3.4.0, and tried updating > the RAID driver, and changing the IO scheduler. Nothing seems to affect > the behavior. Testing using Ext4 (instead of XFS) next. Did you try turning barriers on or off *manually* (explicitly)? With LSI and barriers *on* and ext4 I had less-optimal performance. With Linux MD or (some) 3Ware configurations I had no performance hit. -- Jon -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
