XFS: I/O Error Detected / 2.6.27.39

[Piotr Kandziora]

Hi,

Our environment is following:
- we have 24GB RAM,
- we are using 3ware controller (and it does not report any errors),
- we have one big logical volume (20TB) exported via NFS with large 
amount of small files (about 150k),
- we are doing periodically backup of this logical volume using rsync to 
another server.
- we have kernel 2.6.27.39,

Unfortunately our system is freezing unexpectedly without reason. We 
started investigating this problem and noticed that cache memory is 
slowly increasing.

We tried to dump this cache memory using:
/bin/echo "3" > /proc/sys/vm/drop_caches

In a result, cache was dumped, but in logs we noticed a lot of errors 
with XFS:

[kern.warning] kernel: xfs_iunlink_remove: xfs_inotobp()  returned an 
error 22 on dm-16.  Returning error.
[kern.notice] kernel: xfs_inactive:\011xfs_ifree() returned an error = 
22 on dm-16
[kern.notice] kernel: xfs_force_shutdown(dm-16,0x1) called from line 
1406 of file fs/xfs/xfs_vnodeops.c.  Return address = 0x
[kern.alert] kernel: Filesystem \"dm-16\": I/O Error Detected.  Shutting 
down filesystem: dm-16
[kern.alert] kernel: Please umount the filesystem, and rectify the 
problem(s)
[kern.warning] kernel: xfs_imap_to_bp: xfs_trans_read_buf()returned an 
error 5 on dm-16.  Returning error.
[kern.warning] kernel: xfs_imap_to_bp: xfs_trans_read_buf()returned an 
error 5 on dm-16.  Returning error.
[kern.warning] kernel: xfs_imap_to_bp: xfs_trans_read_buf()returned an 
error 5 on dm-16.  Returning error.

We are wondering if this is problem connected to hardware or rather this 
is XFS problem (if yes, was it fixed?).

Best regards
Piotr K