Hi!
I ran xfs_fsr on my laptops some time ago, for example on my partition
which holds /home. This seemed to work quite well:
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shambala:~> xfs_db -c frag -f /dev/sda2
actual 777855, ideal 737681, fragmentation factor 5.16%
shambala:~> xfs_fsr /dev/sda2
/home start inode=0
shambala:~> xfs_db -c frag -f /dev/sda2
actual 744809, ideal 737681, fragmentation factor 0.96%
shambala:~> xfs_fsr /dev/sda2
/home start inode=0
shambala:~> xfs_db -c frag -f /dev/sda2
actual 744809, ideal 737681, fragmentation factor 0.96%
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As discussed before here there is a limit in what xfs_fsr can do and it
didn't come below 0.96% fragmentation even though the partition has
several GB of free space.
As I restarted KMail after fragmenting it however told me about some
broken indexes. KMail stores index for folders in files. It was able to
restore the indexes.
I can not pinpoint this problem to the defragmentation with xfs_fsr, but
it seemed more than a coincidence to me that it happened directly after I
restarted KMail after the defragmentation.
KMail was running while the fragmentation was taking place and well it
likely had some index files opened. At least it does now that I am
writing that mail:
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shambala:~> lsof +D /home/martin/Mail
COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME
kontact 2787 martin mem REG 8,2 280837
223046853 /home/martin/Mail/.Lichtvoll.directory/.KDE.index
kontact 2787 martin mem REG 8,2 33
119177542 /home/martin/Mail/.templates.index
kontact 2787 martin mem REG 8,2 33
120665290 /home/martin/Mail/.drafts.index
kontact 2787 martin 18u REG 8,2 280837
223046853 /home/martin/Mail/.Lichtvoll.directory/.KDE.index
kontact 2787 martin 19u REG 8,2 33
120665290 /home/martin/Mail/.drafts.index
kontact 2787 martin 20u REG 8,2 33
119177542 /home/martin/Mail/.templates.index
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Could data loss happen when running xfs_fsr on files that are opened by an
application?
I did not came across any other corrupted files except a Mercurial
repository. I can not pinpoint this problem to XFS at all and have no
idea how and when it got corrupted. At least in my backup from some weeks
ago the repository has been okay. Unfortunately I do not know anymore
whether I made a commit to that repository while xfs_fsr was running or
not. But I think I didn't.
The filesystem itself was okay after fragmentation, I checked it via
xfs_check!
I can try to reproduce the problem. Would be handy tough to have an
xfs_fsr that can be limited only to operate on a certain directory and
its files and sub directories. This way I could create a new mailfolder,
copy some mails in there, have it opened so that KMail accesses the index
file and let xfs_fsr only run on this mailfolder.
I can also open a bug report, but I first wanted to ask here.
Regards,
--
Martin 'Helios' Steigerwald - http://www.Lichtvoll.de
GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7
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