From: Carlos Maiolino <cmaiolino@redhat.com>
To: xfs@oss.sgi.com
Subject: Re: XFS: possible memory allocation deadlock in kmem_alloc
Date: Mon, 30 May 2016 11:20:14 +0200 [thread overview]
Message-ID: <20160530092014.GB13872@redhat.com> (raw)
In-Reply-To: <9BD371B3-8A44-481C-B9E4-381BAE0B6B79@gmail.com>
On Mon, May 30, 2016 at 04:48:36PM +0800, baotiao wrote:
> how can I set the extent size hint to a file with command line?
>
> I have google for a lot, but I can't find a answer
>
It can be set with xfs_io, like:
xfs_io -c "extsize 8m" <file> # To set an extent size hint of 8m
Although, it only works if the file is empty, or more specific, the file must
not have any extents allocated
> ----------------------------------------
>
> Github: [1]https://github.com/baotiao
> Blog: [2]http://baotiao.github.io
> Stackoverflow: [3]http://stackoverflow.com/users/634415/baotiao
> Linkedin: [4]http://www.linkedin.com/profile/view?id=145231990
>
> On May 30, 2016, at 13:04, Dave Chinner <[5]david@fromorbit.com> wrote:
>
> On Mon, May 30, 2016 at 12:45:07PM +0800, baotiao wrote:
>
> This machine is running for qemu, the file is qemu qcow file type
> [root@w-openstack20
> /data/nova/instances/7898b630-c4ef-49ab-9ce9-3735e090c282]# file
> disk
> disk: QEMU QCOW Image (v3), has backing file (path
> /data/nova/instances/_base/3f27393376152ac352b2d85703011e38517e),
> 429496729600 bytes
>
> Oh, you're using delta/snapshot based qcow images. That, by it's
> very nature, generates fragmented image files as they are a delta
> over the backing file.
> ....
>
> actual 48421430, ideal 20716, fragmentation factor 99.96%
> How can I solve this problem, what do you suggest me to do?
>
> Use a extent size hint (say 1-8MB) for your qcow2 image files so that
> they don't fragment badly as they are written to.
> Cheers,
> Dave.
> --
> Dave Chinner
> [6]david@fromorbit.com
>
> References
>
> 1. https://github.com/baotiao
> 2. http://baotiao.github.io/
> 3. http://stackoverflow.com/users/634415/baotiao
> 4. http://www.linkedin.com/profile/view?id=145231990
> 5. mailto:david@fromorbit.com
> 6. mailto:david@fromorbit.com
> _______________________________________________
> xfs mailing list
> xfs@oss.sgi.com
> http://oss.sgi.com/mailman/listinfo/xfs
--
Carlos
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next prev parent reply other threads:[~2016-05-30 9:20 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-30 4:45 XFS: possible memory allocation deadlock in kmem_alloc baotiao
2016-05-30 5:04 ` Dave Chinner
2016-05-30 8:48 ` baotiao
2016-05-30 9:20 ` Carlos Maiolino [this message]
2016-05-31 2:43 ` 陈宗志
2016-05-31 3:10 ` Dave Chinner
2016-05-31 11:00 ` 陈宗志
2016-05-31 12:14 ` Carlos Maiolino
2019-11-04 23:38 Chris Holcombe
2019-11-05 0:01 ` Darrick J. Wong
2019-11-05 0:31 ` Eric Sandeen
[not found] ` <CAC752AmahECFry9x=pvqDkwQUj1PEJjoWGa2KFG1uaTzT1Bbnw@mail.gmail.com>
2019-11-05 4:21 ` Eric Sandeen
2019-11-05 16:25 ` Chris Holcombe
2019-11-05 17:11 ` Eric Sandeen
2019-11-05 19:53 ` Chris Holcombe
2019-11-05 20:08 ` Eric Sandeen
[not found] ` <CAC752AnZ4biDGk6V17URQm5YVp=MwZBhiMH8=t733zaypxUsmA@mail.gmail.com>
2019-11-05 20:47 ` Eric Sandeen
[not found] ` <CAC752A=y9PMEQ1e4mXskha1GFeKXWi8PsdBW-nX40pgFCYp1Uw@mail.gmail.com>
2019-11-05 21:23 ` Eric Sandeen
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