Jan-Frode Myklebust wrote:
<snip>
So I am a bit conserned I might get the same problem as Charles
Steinkuehler if I ever need to run xfs_repair.. Charles did you find a
solution for your problem?
I found a solution...I switched to JFS. ;-P
While my problems with XFS may have been greatly magnified due to
low-level hardware probems (fixed by switching to a Promise SATA
controller), there seem to be enough folks reporting problems with XFS +
LVM + Software RAID5 that I would hesitate to use this combination in
production without a *LOT* of testing I didn't have time for. I don't
currently need either extended attribute support or the larger
filesystem sizes available in XFS, so JFS is working fine for me.
NOTE: A quick check on my system (running debian testing, 2.6.6-1-k7
kernel, Promise TX4 w/4x now-working SATA drives) and the first of my
stress tests passes (lvcreate, mkfs.xfs, mount, bonnie++, umount,
xfs_repair). I don't have enough room for the second stress-test I was
using (rsync apx 150G of data from an ext3 partition, umount, and
xfs_repair). I suspect if you can extract/compile the kernel tarball,
umount, and get a clean xfs_repair, things are probably working normally.
I'd probably also try a hard power-off shutdown while extracting the
kernel tarball (or compiling, or otherwise pounding on the FS) followed
by an xfs_repair to make sure you can return to normal from a real-world
error condition (probably a good idea to mount all but the volume under
test as read-only before-hand!). I was seeing the "switching cache
buffer size" messages when running xfs_repair (and IIRC when mounting or
unmounting), not in normal operation (once I formatted with size=4096),
so I'd definately try to test xfs_repair on a 'broken' FS before
trusting it with production data.
Finally, while unrelated to LVM/RAID5, based on information I've
absorbed in my extensive googling, XFS seems to have a tendency to keep
data in a write-cache, which combined with it's journal replay
characteristics on startup (ie: zeroing unclean files) can cause
problems if your system is ever subject to unclean shutdowns. Hopefully
someone on-list with more knowledge of XFS internals can comment on how
accurate this is.
--
Charles Steinkuehler
charles@xxxxxxxxxxxxxxxx
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