Hi Peter,
As for reporting bugs ... http://bugs.mysql.com/bug.php?id=7437 http://bugs.mysql.com/bug.php?id=10437
We have found Opteron w/ Mysql to be an extremely buggy platform, especially under linux 2.6, but granted, we are running Fedora. Perhaps we will try Suse, but I feel I have heard similar reports (from Friendster) about their use of Suse 2.6 and Opterons being similarly slow.
We are currently running MyIsam tables, but plan on switching to Innodb in the next month or two btw, so our performance problems are w/ MyIsam.
Greg
Peter Zaitsev wrote:
On Fri, 2005-05-06 at 19:01, Greg Whalin wrote:
What drives are you using? For SCSI RAID, you definitly want deadline scheduler. That said, even after the switch to deadline, we saw our Opteron's running way slow (compared to older slower Xeons). Whatever the problem is, we fought it for quite a while (though difficult to test too much w/ production dbs) and ended up rolling back to 2.4.
One more thing to try, if you have smart RAID would be "noop"
scheduler, to let hardware to do the job. Smart optimizations OS do to
reduce head movement may not make sense for RAID. In practice I've
however seen close results.
Also which storage engine are you using ?
One of the things which was changed in 2.6 for some hardware
configurations is fsync() performance. It was cases in some cases,
so it was instant.
This for example explained in many cases why people moving from IDE devices to much faster SCSI devices may observe performance degradation (IDE with 2.4 has typically fake fsync)
In general we have very positive feedback from using Opterons with
MySQL at this point. Sometimes it takes time to make it work right,
especially it was the case when they were new but when it flies. Practically same applies to EM64T - It is very good to have now two
inexpensive 64bit platforms available.
We're getting some feedback about problems on some Fedora Core versions, well this is "bleeding edge" distribution so I'm nothing but surprised.
SuSE both in SLES and Professional variants seems to work very well with Opterons as well as recent RH EL.
Speaking about MySQL problems - if you have any MySQL issues on Opterons, please report them as bugs and we'll troubleshoot it.
Kevin Burton wrote:
Kevin Burton wrote:
Greg Whalin wrote:
Deadline was much faster. Using sysbench:
test:
sysbench --num-threads=16 --test=fileio --file-total-size=20G --file-test-mode=rndrw run
So... FYI. I rebooted with elevator=deadline as a kernel param.
db2:~# cat /sys/block/sda/queue/scheduler noop anticipatory [deadline] cfq
(which I assume means I'm now running deadline. Is there any other way to find out?)
And no performance diff. Note that you're benchmarks only show a 20M addition overhead. We're about 60x too slow for these drives so I'm not sure what could be going on here :-/
Kevin
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