From: Eric Sandeen <sandeen@redhat.com>
To: Karsten Weiss <K.Weiss@science-computing.de>
Cc: Dmitry Monakhov <dmonakhov@openvz.org>,
"linux-ext4@vger.kernel.org" <linux-ext4@vger.kernel.org>
Subject: Re: Bad ext4 sync performance on 16 TB GPT partition
Date: Fri, 26 Feb 2010 11:49:54 -0600 [thread overview]
Message-ID: <4B8809C2.2000300@redhat.com> (raw)
In-Reply-To: <alpine.LNX.2.00.1002261546380.18232@wong.science-computing.de>
Karsten Weiss wrote:
> Hi Dmitry!
>
> On Fri, 26 Feb 2010, Dmitry Monakhov wrote:
>
...
>>> * I did not try a vanilla kernel so far.
>> IMHO It would be really good to know vanilla kernel's stats.
>
> I did a quick&dirty compilation of vanilla kernel 2.6.33 and repeated the
> test:
>
> # /usr/bin/time bash -c "dd if=/dev/zero of=/mnt/large/10GB bs=1M count=10000 && sync"
> 10000+0 records in
> 10000+0 records out
> 10485760000 bytes (10 GB) copied, 50.044 seconds, 210 MB/s
> 0.01user 13.76system 1:04.75elapsed 21%CPU (0avgtext+0avgdata 6224maxresident)k
> 0inputs+0outputs (0major+1049minor)pagefaults 0swaps
>
> => The problem shows only with the CentOS / Red Hat 5.4 kernels (including
> RH's test kernel 2.6.18-190.el5). Aadmittedly ext4 is only a technology
> preview in 5.4...
>
> I've also tried the latest CentOS 5.3 kernel-2.6.18-128.7.1.el5 but
> couldn't mount the device (with -t ext4dev).
>
> 2.6.18-164.el5 (the initial CentOS 5.4 kernel) has the bug, too.
>
> I'm willing to test patches if somebody wants to debug the problem.
Ok, that's interesting. We've not had bona-fide RHEL customers report
the problem, but then maybe it hasn't been tested this way.
2.6.18-178.el5 and beyond is based on the 2.6.32 codebase for ext4.
Testing generic 2.6.32 might also be interesting as a datapoint,
if you're willing.
-Eric
next prev parent reply other threads:[~2010-02-26 17:50 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-02-26 10:18 Bad ext4 sync performance on 16 TB GPT partition Karsten Weiss
2010-02-26 11:33 ` Karsten Weiss
2010-02-26 11:46 ` Dmitry Monakhov
2010-02-26 15:47 ` Karsten Weiss
2010-02-26 17:49 ` Eric Sandeen [this message]
2010-03-01 8:57 ` Karsten Weiss
2010-03-01 16:22 ` Eric Sandeen
2010-03-12 11:37 ` Karsten Weiss
2010-03-12 15:20 ` Eric Sandeen
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