Re: xfs_repair segfaults with ag_stride option

Eric Sandeen
2012-02-06T05:58:27Z

On 2/5/12 6:50 PM, Tom Crane wrote:
> Hi Christoph,
> Many thanks for the quick response and the patch. It was a big help.
> I was able to repair our 60TB FS in about 30 hours. I have a couple
> of questions;
>
> (1) The steps in the progress report seem a little strange. See the
> attachment. Is this expected?
>
> (2) This may be a little out of band but I have heard second hand
> reports from another sysadmin that the xfs tools which come with SLC5
> (our current Linux distro) should not be relied upon and that SLC6
> should be used. Our 60TB FS is significantly fragmented (~40%) and I
> would very much like to run xfs_fsr on it. Given that I have built
> the latest xfsprogs, is there any reason I should be afraid of
> running xfs_fsr, on the FS which comes with SLC5? Unfortunately I
> don't have ~60TB spare storage space elsewhere to backup the FS
> before defragging. What would you advise?>
> Many thanks

Newer tools are fine to use on older filesystems, there should be no
issue there.

running fsr can cause an awful lot of IO, and a lot of file reorganization.
(meaning, they will get moved to new locations on disk, etc).

How bad is it, really? How did you arrive at the 40% number? Unless
you see perf problems which you know you can attribute to fragmentation,
I might not worry about it.

You can also check the fragmentation of individual files with the
xfs_bmap tool.

-Eric

> Tom.
>
> Christoph Hellwig wrote:
>> Hi Tom,
>>
>> On Wed, Feb 01, 2012 at 01:36:12PM +0000, Tom Crane wrote:
>>
>>> Dear XFS Support,
>>> I am attempting to use xfs_repair to fix a damaged FS but always
>>> get a segfault if and only if -o ag_stride is specified. I have
>>> tried ag_stride=2,8,16 & 32. The FS is approx 60T. I can't find
>>> reports of this particular problem on the mailing list archive.
>>> Further details are;
>>>
>>> xfs_repair version 3.1.7, recently downloaded via git repository.
>>> uname -a
>>> Linux store3 2.6.18-274.17.1.el5 #1 SMP Wed Jan 11 11:10:32 CET 2012
>>> x86_64 x86_64 x86_64 GNU/Linux
>>>
>>
>> Thanks for the detailed bug report.
>>
>> Can you please try the attached patch?
>>
>>
>
>
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