[dm-devel] Re: Snapshot merging
Mikulas Patocka
mpatocka at redhat.com
Wed Sep 9 15:47:27 UTC 2009
Hi
I found one bug in the userspace code --- start merging, then from the
other console deactivate the origin volume with lvchange -an, then wait
next 15 seconds for the next poll interval:
the poll process will think that the merging finished, removing the
snapshot, leaving partially merged origin and causing data corruption:
[slunicko:~]# lvconvert -M vg1/lv2_snap1
Merging of volume lv2_snap1 started.
lv2: Merged: 13.1%
( .... deactivate the volume from the other console ....)
lv2: Merged: -1.0%
Merge into logical volume lv2 finished.
Logical volume "snapshot4" successfully removed
Maybe this bug was in my code too, I don't remember.
Otherwise, the code seems stable, I didn't see anything wrong, I tried to
crash it while merging and it resumed without data corruption.
Mikulas
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