cannot defrag volume, fragmentation factor 21.73%

Stan Hoeppner stan at
Mon Oct 18 15:16:40 CDT 2010

Richard Ems put forth on 10/18/2010 7:09 AM:

> I ran several times xfs_fsr, but the 21.73% factor stays there.
> There where some busy or modified files on which I started xfs_fsr later
> again, but this ones where small files and the 21.73% is still there.
> Any ideas?

Yes.  The answer is in a thread in last month's archive:

Dave Chinner put forth on 9/11/2010 3:23 AM:

> xfs_db used buffered IO on the block device, which is not coherent
> with the filesystem. If you are using it on an active filesystem,
> then running "echo 1 > /proc/sys/vm/drop_caches" before you run
> xfs_db should make it read from disk at least once....


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