>>> "Joshua D. Drake" <jd(at)commandprompt(dot)com> 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(at)DBUTL-PG:/var/pgsql/data/test> cat /proc/version
Linux version 2.6.5-7.287.3-bigsmp (geeko(at)buildhost) (gcc version 3.3.3
(SuSE Linux)) #1 SMP Tue Oct 2 07:31:36 UTC 2007
kgrittn(at)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(at)DBUTL-PG:/var/pgsql/data/test> cat /etc/SuSE-release
SUSE LINUX Enterprise Server 9 (i586)
VERSION = 9
PATCHLEVEL = 3
new:
kgrittn(at)SAWYER-PG:~> cat /proc/version
Linux version 2.6.16.60-0.27-smp (geeko(at)buildhost) (gcc version 4.1.2
20070115 (SUSE Linux)) #1 SMP Mon Jul 28 12:55:32 UTC 2008
kgrittn(at)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(at)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