> From: Koray Eyidoğan <korayey@xxxxxxxxx> >To: Thomas SIMON <tsimon@xxxxxxxxxxx> >Cc: pgsql-admin@xxxxxxxxxxxxxx >Sent: Monday, 18 May 2015, 14:51 >Subject: Re: Performances issues with SSD volume ? > > > >Hi Thomas, > > >3.2 kernel may be #1 cause of your I/O load problem: > > >http://www.databasesoup.com/2014/09/why-you-need-to-avoid-linux-kernel-32.html > >https://medium.com/postgresql-talk/benchmarking-postgresql-with-different-linux-kernel-versions-on-ubuntu-lts-e61d57b70dd4 > > > >Have a nice day. > > >Koray Likely 3.2 kernel isn't helping, but I think we need much more information before jumping to conclusions. You say you're IO bound, so some output from sar / iostat / dstat and pg_stat_activity etc before and during the issue would be of use. Also: System memory size SSD Model numbers and how many Raid controller Partition allignments and stripe sizes Kernel options Filesystem used and mount options IO Scheduler Postgresql version and configuration Connection pool sizing Perhaps you could thow us the output of some of these: fdisk -l cat /etc/mtab cat /sys/block/<ssd device>/queue/scheduler sysctl kernel | grep sched sysctl vm select * from pg_stat_activity select name, setting from pg_settings lspci | grep -E 'RAID|SCSI|IDE|SATA' -- Sent via pgsql-admin mailing list (pgsql-admin@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-admin
