[linux-lvm] Removing snapshot often fails

[Danilo Godec]

On 04/03/2012 04:12 PM, Peter Rajnoha wrote:
> On 04/03/2012 03:45 PM, Danilo Godec wrote:
>> However I discovered that often removing a snapshot fails - unfortunately it's quite unpredictable, as sometimes it works on next try but sometimes it fails 20 times in a row - making it very unpleasant for scripting...
> What's the lvm2 version you're using?

The version is 2.02.67 from 'official' OpenSuSE 11.4 updates.

> With a very high probability, this is caused by the "watch" udev rule.
> Do you have "udisks" installed? This one sets in its
> '/lib/udev/rules.d/80-udisks.rules' the 'KERNEL=="dm-*", OPTIONS+="watch"'
> which causes the udev event to be generated and processed while trying to
> close the device.

Yes, udisks package is installed and above mentioned rule file is in 
place. Not sure if it's really needed, though.

> See also https://bugzilla.redhat.com/show_bug.cgi?id=577798 for more
> information about the problem.

It seems that 'udevadm control --stop-exec-queue' before removing the 
snapshot could be a viable workaround.

> Recently, we've added a retry loop when trying to remove a device-mapper
> device. This will try to remove the device several times before it fails
> completely (libdevmapper v1.02.68, lvm2 v2.02.89 released 26th Jan. 2012).
> Though you still get an error saying "remove ioctl failed" on each failed retry...


Thank you,

          Danilo