On 02/07/2013 01:42 PM, Andres Toomsalu wrote:
Hi,
We have experienced a situation where we are left with large number
of thin snapshots (around 500) and snapshot removal wont work anymore
(we suspect a lock-up situation caused by trying to remove thin
snapshots that is still mounted - thou its not verified yet - just a
speculation). The only path to recover seems to be disabling all
thin volumes from fstab and booting into single-user mode - where
lvremove -f usually succeeds on these thin snapshots. But LVM init
and lvremove take a huge amount of time with large number of
snapshots - initial LVM activation is going on about 6-8 minutes at
least and every lvremove takes ca 20-50 sec - depending on snapshot
count left. After snapshots are removed thin volumes can be enabled
again and fsck-ed and resuming normal operations.
Hello Andres, could you provide the following information:
Which version of lvm?
Is lvmetad used?
grep lvmetad /etc/lvm/lvm.conf
pgrep lvmetad
RHEL6.3 version of lvmetad had a serious performance issue with many
[thin] snapshots, which should be solved in the latest release
(lvm2-2.02.98)
Could you check the memory usage while the command is running?
Also there were a high memory usage problems fixed in the recent version.
-- Marian
Althou we are not yet sure what is causing the lockup - so that
snapshots cant be removed anymore without reboot - its also
problematic that with large numbers of snapshots all LVM device
operations are dead slow. I hope this issue can be addressed somehow
in the future.
Kind regards,
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