From: Roman Mamedov <rm@romanrm.net>
To: Martin Boutin <martboutin@gmail.com>
Cc: "Kernel.org-Linux-RAID" <linux-raid@vger.kernel.org>,
"Kernel.org-Linux-XFS" <linux-xfs@vger.kernel.org>,
"Kernel.org-Linux-EXT4" <linux-ext4@vger.kernel.org>
Subject: Re: Filesystem writes on RAID5 too slow
Date: Tue, 19 Nov 2013 00:41:40 +0600 [thread overview]
Message-ID: <20131119004140.3fea96df@natsu> (raw)
In-Reply-To: <CACtJ3HZxp6xEjY_wOucCcqX4scNzEGuiAsovQYObJS9whtYJsQ@mail.gmail.com>
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On Mon, 18 Nov 2013 11:02:15 -0500
Martin Boutin <martboutin@gmail.com> wrote:
> I have the md0 raid device formatted as ext3 with a 4k block size, and
> stride and stripes correctly chosen to match the raid chunk size, that
> is, stride=128,stripe-width=256.
What is your stripe cache size?
http://peterkieser.com/2009/11/29/raid-mdraid-stripe_cache_size-vs-write-transfer/
> The command line for measuring filesystem read and write speeds was:
>
> $ dd if=/tmp/diskmnt/filerd.zero of=/dev/null bs=1M count=1000 iflag=direct
> $ dd if=/dev/zero of=/tmp/diskmnt/filewr.zero bs=1M count=1000 oflag=direct
Try testing with "fdatasync" instead of "direct" here.
--
With respect,
Roman
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next prev parent reply other threads:[~2013-11-18 18:41 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-18 16:02 Filesystem writes on RAID5 too slow Martin Boutin
2013-11-18 18:28 ` Eric Sandeen
2013-11-19 0:57 ` Dave Chinner
2013-11-21 9:11 ` Martin Boutin
2013-11-21 9:26 ` Dave Chinner
2013-11-21 9:50 ` Martin Boutin
2013-11-21 13:31 ` Martin Boutin
2013-11-21 16:35 ` Martin Boutin
2013-11-21 23:41 ` Dave Chinner
2013-11-22 9:21 ` Christoph Hellwig
2013-11-22 22:40 ` Dave Chinner
2013-11-23 8:41 ` Christoph Hellwig
2013-11-24 23:21 ` Dave Chinner
2013-11-22 13:33 ` Martin Boutin
2013-12-10 19:18 ` Christoph Hellwig
2013-12-11 0:27 ` Dave Chinner
2013-12-11 19:09 ` Ben Myers
2013-11-18 18:41 ` Roman Mamedov [this message]
2013-11-18 19:25 ` Roman Mamedov
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