>>> "Joshua D. Drake" <jd@xxxxxxxxxxxxxxxxx> wrote: > On Thu, 2008-11-06 at 13:02 -0600, Kevin Grittner wrote: >> the new kernel >> defaulted to using write barriers, while the old kernel didn't. Since >> we have a BBU RAID controller, we will add nobarrier to the fstab >> entries. This makes file creation and unlink each about 20 times >> faster. > > Woah... which version of the kernel was old and new? old: kgrittn@DBUTL-PG:/var/pgsql/data/test> cat /proc/version Linux version 2.6.5-7.287.3-bigsmp (geeko@buildhost) (gcc version 3.3.3 (SuSE Linux)) #1 SMP Tue Oct 2 07:31:36 UTC 2007 kgrittn@DBUTL-PG:/var/pgsql/data/test> uname -a Linux DBUTL-PG 2.6.5-7.287.3-bigsmp #1 SMP Tue Oct 2 07:31:36 UTC 2007 i686 i686 i386 GNU/Linux kgrittn@DBUTL-PG:/var/pgsql/data/test> cat /etc/SuSE-release SUSE LINUX Enterprise Server 9 (i586) VERSION = 9 PATCHLEVEL = 3 new: kgrittn@SAWYER-PG:~> cat /proc/version Linux version 2.6.16.60-0.27-smp (geeko@buildhost) (gcc version 4.1.2 20070115 (SUSE Linux)) #1 SMP Mon Jul 28 12:55:32 UTC 2008 kgrittn@SAWYER-PG:~> uname -a Linux SAWYER-PG 2.6.16.60-0.27-smp #1 SMP Mon Jul 28 12:55:32 UTC 2008 x86_64 x86_64 x86_64 GNU/Linux kgrittn@SAWYER-PG:~> cat /etc/SuSE-release SUSE Linux Enterprise Server 10 (x86_64) VERSION = 10 PATCHLEVEL = 2 To be clear, file create and unlink speeds are almost the same between the two kernels without write barriers; the difference is that they were in effect by default in the newer kernel. -Kevin -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
