[linux-lvm] snapshots with XFS and 2.6 kernel

[David Powers <david grayskies net>]

I was attempting to
implement a quick snapshot backup solution using lvm2, XFS, and
snapshots on a 2.6 kernel.? After some very odd hangs I started hunting
around in the lists and came across some posts that snapshots were not
yet properly implemented in 2.6.? These were from a few months ago and
a quick scan of the lvm2 tarball (in particular WHATS_NEW and README)
doesn't seem to indicate that snaphots should be avoided.? So the
question is, are snapshots usable?? And if they aren't where would I
find more current information about when they will be?? as it stands
now creating a snapshot tends to produce:

disk1 snapshots # lvcreate -L5G -nsnaptest -s /dev/filestore/archive 
? device-mapper ioctl cmd 9 failed: Invalid argument
? Couldn't load device 'filestore-snaptest'.
? Problem reactivating origin archive

an lvscan afterwards shows the snapshot:

disk1 snapshots # lvscan
? ACTIVE?? Original '/dev/filestore/archive' [60.00 GB] next free
(default)
? ACTIVE??????????? '/dev/filestore/groups' [50.00 GB] next free
(default)
? ACTIVE??????????? '/dev/filestore/personal' [50.00 GB] next free
(default)
? ACTIVE?? Snapshot '/dev/filestore/snaptest' [5.00 GB] next free
(default)

but the device isn't actually created and it takes hard rebooting and a
lot of fiddling and poking to delete it.? Any help or insight is
appreciated.

-David