Alex Dean wrote:
On Oct 1, 2010, at 11:01 AM, Eric Shubert wrote:
Alex Dean wrote:
On Oct 1, 2010, at 3:32 AM, der.hans wrote:
Am 30. Sep, 2010 schwätzte Eric Shubert so:
Which elevator is being used?
(cat /sys/block/sda/queue/scheduler)
noop anticipatory deadline [cfq]
Using async i/o? Synchronous writes are very slow.
Hmm, not familiar with libaio. Looks like we have it installed.
I presume ext3, since you referred to noatime. If you have directories with
many files (e.g. Maildir), dir_index option can help.
Yeah, ext3. Mostly it's a few DB files and some log files. No mail
directories.
FWIW: A few years ago, I recall seeing somewhat-improved benchmark performance
from MySQL after switching to the deadline scheduler.
I'd give that a shot - can't hurt to try.
# echo deadline >/sys/block/sda/queue/scheduler
I thought it required a reboot to change scheduler. Maybe that's changed in
more recent kernels. (This was RHEL4, so 2.6.9-something.)
alex
You need to include the elevator= kernel parameter to make the change
persist. You can use different schedulers for different devices by
including the echo command in the /etc/rc.local file (overriding the
elevator parameter, per device).
--
-Eric 'shubes'
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