Re: XFS: possible memory allocation deadlock in kmem_alloc

[éåå <baotiao@xxxxxxxxx>]

I have fint the way to change the extent size hint
mkfs.xfs -r extsize=40960 /dev/sda1

but I should rebuild the disk, do you have a way more smooth?

On Mon, May 30, 2016 at 4:48 PM, baotiao <baotiao@xxxxxxxxx> wrote:

how can I set the extent size hint to a file with command line?Â

I have google for a lot, but I can't find a answer

----------------------------------------
Â

Github:Âhttps://github.com/baotiao
Blog: http://baotiao.github.io
Stackoverflow: http://stackoverflow.com/users/634415/baotiaoÂ

Linkedin: http://www.linkedin.com/profile/view?id=145231990

On May 30, 2016, at 13:04, Dave Chinner <david@xxxxxxxxxxxxx> wrote:

On Mon, May 30, 2016 at 12:45:07PM +0800, baotiao wrote:

This machine is running for qemu, Âthe 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
david@xxxxxxxxxxxxx

--

---
Blog: http://www.chenzongzhi.info
Twitter: https://twitter.com/baotiao
Git: https://github.com/baotiao