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Date: Mon, 01 Mar 2010 01:39:18 -0700
From: Andreas Dilger <adilger@sun.com>
Subject: Re: EXT4 is ~2X as slow as XFS (593MB/s vs 304MB/s) for writes?
In-reply-to: <alpine.DEB.2.00.1002280628550.22822@p34.internal.lan>
To: Justin Piszcz <jpiszcz@lucidpixels.com>
Cc: tytso@mit.edu, Eric Sandeen <sandeen@redhat.com>,
       linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org,
       Alan Piszcz <ap@solarrain.com>
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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.

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.