drive performance

[Eric Shubert]

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

Also, what are the bus speeds of the various hosts? Could that be your 
bottleneck?

Or cabling perhaps? Long SATA cables can be problematic. I haven't seen 
a bad SATA cable yet (that I know of), but I'd try to eliminate that as 
a possibility. (I detest HW problems, but they do occasionally exist)

-- 
-Eric 'shubes'