"...like if the disk/filesystem gets slower during one hour or so"
What about a different scheduled task on the system, not necessarily Postgres related? On Mon, Jul 29, 2013 at 9:17 AM, German Becker <german.bec...@gmail.com>wrote: > Alvaro, > > Thanks for your reply. I believe that the only possibility is autovacum > activity I will check that. Anyway what puzzles me is that > the throughput does not increase like i might expect if there where high > VACUUM activity, only the WAIT TIME and thus the UTILIZATION. Is like if > the disk/filesystem gets slower during one hour or so... > > > On Fri, Jul 26, 2013 at 5:27 PM, Alvaro Herrera > <alvhe...@2ndquadrant.com>wrote: > >> German Becker escribió: >> > Hi list, >> > >> > I am running Postgres 9.1 on Ubuntu 12.04. I have a dedicated disk for >> > pg_xlog, using ext4 filesystem with journaling in writeback mode >> > During high load times, the disk usage is arround 40%. The IO write >> time is >> > constant at about 3ms. On certain occasions roughly once in 15 days, >> the >> > IO write time goes up to about 10ms. This makes the disk usage go up to >> > almost 100%, probably saturation, and the INSERTS DELETES UPDATES run >> > considerable slower than normal.This lasts for about 2 hours and then >> the >> > latency goes back to 3ms and everything is normal again. >> > Has anyone seen this behavior? What could be causing the increase in >> > latency? >> >> Can you correlate these episodes with autovacuum activity? Or perhaps >> backups are being taken (maybe a new base backup is taken every 15 >> days)? >> >> -- >> Álvaro Herrera http://www.2ndQuadrant.com/ >> PostgreSQL Development, 24x7 Support, Training & Services >> > >
