On Wed, Mar 20, 2002 at 11:30:33AM +0000, Ian Hardy wrote:
> I note that my exchange of emails with Steve Lord yesterday
> "Re: XFS NFS server Oops" with regards to checking for
> fragmentation and reducing fragmentation using 'xfs_fsr' has
> generated a followup thread "Re: Fragmentation (was: XFS NFS
> server Oops)" and some interest in deframenting XFS file systems.
>
> I'd recommend that you DON'T all rush to run 'xfs_fsr', at least
> until we've got some more feedback/info from the XFS experts
> at SGI. As advised I ran 'xfs_fsr' last night, it had completed
> when I got into work in the morning, so I ran 'xfs_db' in order
> to check fragmentation levels again:
>
> # xfs_db -r /dev/md0
> xfs_db: frag -f
> Segmentation fault (core dumped)
>
> Whats more it then shutdown the filesystem (from 'messages'):
>
> Mar 20 09:30:17 blue00 kernel: xfs_force_shutdown(md(9,0),0x8) called from
> line
> 1039 of file xfs_trans.c. Return address = 0xc01e2179
> Mar 20 09:30:17 blue00 kernel: Corruption of in-memory data detected.
> Shutting
> down filesystem: md(9,0)
> Mar 20 09:30:17 blue00 kernel: Please umount the filesystem, and rectify the
> problem(s)
>
> I rebooted the server and ran 'xfs_check' on the filesystem that showed
> a number of errors, which 'xfs_repair' fixed (I'll post some more details
> shortly).
>
> While its (very) possible that the above problem was due to underlying
> problems with my filesystem, it is also possible that 'xfs_fsr' had
> some bad effect on the filesystem. Worth getting some feedback from the
> XFS experts before too many people rush to run 'xfs_fsr' !?
>
> By the way I seem to remember a lot of SGI Irix users (including me) had
> various problems with 'xfs_fsr' when SGI first introduced it (or enabled
> its default running from cron) under Irix a few years ago. I believe
> these problems where fixed, however, I still don't routinely run
> 'xfs_fsr' on my Irix servers.
>
>
> Ian
>
> /////////////Technical Coordination, Research Services////////////////////
> Ian Hardy
> Computing Services
> Southampton University email: idh@xxxxxxxxxxx
> Southampton S017 1BJ, UK. i.d.hardy@xxxxxxxxxxx
> \\'BUGS: The notion of errors is ill-defined' (IRIX man page for netstat)\
>
Just my $0.02 worth on the subject of safety of xfs_fsr:
I have been running xfs_fsr from cron (just like on my Irix systems) ever since
I discovered it back in November with no problems whatsoever. I have aprox. 10
Linux systems set up this way.
Russ
--
Russel H. Ingram
Gargoyle Computer Consulting
(307)742-1361 or (307)760-1317
www.gargoylecc.com
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