From: Wes <wt75@gazeta.pl>
To: linux-raid@vger.kernel.org
Subject: Re: raid10 centos5 vs. centos6 300% worse random write performance
Date: Mon, 12 Aug 2013 08:43:13 +0000 (UTC) [thread overview]
Message-ID: <loom.20130812T104037-602@post.gmane.org> (raw)
In-Reply-To: 51F4B034.3040801@hardwarefreak.com
Stan Hoeppner <stan <at> hardwarefreak.com> writes:
> ~$ cat /sys/block/sda/queue/scheduler
> [CFQ] noop deadline
> Wes, yours will show CFQ probably as the default on RHEL/CentOS. You'll
> want deadline for best seek and all around performance. So:
> ~$ echo deadline > /sys/block/sda/queue/scheduler
> Add that to an init script or cron entry so it sets on every boot.
> Barriers are not an issue with this test.
>
Thank you all. The issue is now closed.
RHEL5 was not doing cache flush right. It was only corrected in 2.6.32+
After removing O_SYNC from seekmark the results are now comparable.
Actually it is hard to find a linux raw device random R/W benchmark tool and
seekmark being the most popular fails when comparing pre and post 2.6.32
systems (unless you remove O_SYNC).
next prev parent reply other threads:[~2013-08-12 8:43 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-25 10:11 raid10 centos5 vs. centos6 300% worse random write performance Wes
2013-07-25 11:44 ` Mikael Abrahamsson
2013-07-25 12:23 ` Wes
2013-07-25 18:49 ` Wes
2013-07-27 20:22 ` Wes
2013-07-27 21:01 ` Marcus Sorensen
2013-07-28 5:46 ` Stan Hoeppner
2013-08-12 8:43 ` Wes [this message]
2013-08-12 19:25 ` Stan Hoeppner
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