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Message-ID: <alpine.DEB.2.00.1003010419090.20072@p34.internal.lan>
Date: Mon, 1 Mar 2010 04:21:03 -0500 (EST)
From: Justin Piszcz <jpiszcz@...idpixels.com>
To: Andreas Dilger <adilger@....com>
cc: tytso@....edu, Eric Sandeen <sandeen@...hat.com>,
linux-ext4@...r.kernel.org, linux-kernel@...r.kernel.org,
Alan Piszcz <ap@...arrain.com>
Subject: Re: EXT4 is ~2X as slow as XFS (593MB/s vs 304MB/s) for writes?
On Mon, 1 Mar 2010, Andreas Dilger wrote:
> On 2010-02-28, at 07:55, Justin Piszcz wrote:
>> === CREATE RAID-0 WITH 11 DISKS
>
>
> Have you tried testing with "nice" numbers of disks in your RAID set (e.g. 8
> disks for RAID-0, 9 for RAID-5, 10 for RAID-6)? The mballoc code is really
> much better tuned for power-of-two sized allocations.
Hi,
Yes, the second system (RAID-5) has 8 disks and it shows the same
performance problems with ext4 and not XFS (as shown from previous
e-mail), where XFS usually got 500-600MiB/s for writes.
http://groups.google.com/group/linux.kernel/browse_thread/thread/e7b189bcaa2c1cb4/ad6c2a54b678cf5f?show_docid=ad6c2a54b678cf5f&pli=1
For the RAID-5 (from earlier testing): <- This one has 8 disks.
-o data=writeback,nobarrier:
10737418240 bytes (11 GB) copied, 48.7335 s, 220 MB/s
-o data=writeback,nobarrier,nodelalloc:
10737418240 bytes (11 GB) copied, 30.5425 s, 352 MB/s
An increase of 132MiB/s.
Justin.
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