Gluster users - Mar 2011 - Quick question regarding xfs_repair

Hello,

 

I have recently had an issue with a RAID volume where a few bad logical
sectors were generated and propagated into the XFS filesystem above it. The
XFS file system is 1 of 4 volumes that are residing beneath a Gluster 3.0
distributed cluster config:

 

volume distribute

    type cluster/distribute

    subvolumes 192.160.200.11-1 192.160.200.11-2 192.160.200.12-1
192.160.200.12-2

end-volume

 

My question has two parts.

 

1.       If I perform an xfs_repair will gluster become out of sync with the
filesystem in lieu of repairs?

2.       Can I trust the backups I performed after these issues cropped up
as a result of the distribution of files across the nodes? Ie, a file is
only ? complete or would gluster complain and make that file unavailable as
it should?

 

Thanks.

 



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On 03/14/2011 12:50 PM, Terry Haley wrote:
> Hello,
[...]
> My question has two parts.
>
>
>
> 1.       If I perform an xfs_repair will gluster become out of sync with
the
> filesystem in lieu of repairs?
If the xfs_repair modifies the extended attributes, it is possible that 
the gluster file system will appear to be inconsistent.  Same issue 
would be with ext* and fsck.  Gluster team would need to respond to this.
> 2.       Can I trust the backups I performed after these issues cropped up
> as a result of the distribution of files across the nodes? Ie, a file is
> only ? complete or would gluster complain and make that file unavailable as
> it should?
Good question.  Can you verify that the data stored on the corrupted 
RAID hasn't been replicated to the other nodes?  If so, easiest route 
might be a RAID rebuild, and then a file system wipe on the effected 
node, followed by a resync (assuming you are doing a replicated design).

If the bad data's been replicated, then you probably have to trash that 
data (and do something similar to the above anyway).

Does your RAID kit have a scan/check function?  We do this with our 
units (both hardware/software RAID), and schedule full scans at least 
weekly.  Strongly advise something similar if you aren't doing it already.

Regards,

Joe

-- 
Joseph Landman, Ph.D
Founder and CEO
Scalable Informatics Inc.
email: landman at scalableinformatics.com
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