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Re: [linux-lvm] clvmd leaving kernel dlm uncontrolled lockspace

On 06/05/13 17:13, David Teigland wrote:
On Wed, Jun 05, 2013 at 03:23:32PM +0200, Andreas Pflug wrote:
A few different topics wrapped together there:

- With kill -9 clvmd (possibly combined with dlm_tool leave clvmd),
   you can manually clear/remove a userland lockspace like clvmd.

I had some clvmd instances not starting up correctly, remaining in nowhereland...

- If clvmd is blocked in the kernel in uninterruptible sleep, then
   the kill above will not work.  To make kill work, you'd locate the
   particular sleep in the kernel and determine if there's a way to
   make it interruptible, and cleanly back it out.

- If clvmd is blocked in the kernel for >120s, you probably want to
   investigate what is causing that, rather than being too hasty
   killing clvmd.

- If corosync or dlm_controld are killed while dlm lockspaces exist,
   they become "uncontrolled" and would need to be forcibly cleaned up.
   This cleanup may be possible to implement for userland lockspaces,
   but it's not been clear that the benefits would greatly outweigh
   using reboot for this.

Any of those programs might get a problem, so either they should re-attach to the lockspace, or a cleanup should be possible. If (as in my case) the host is a xen host with san storage you wouldn't like to reboot it... In my naive imagination, an orphaned lockspace is just some allocated memory that should't be too hard to free.

- Killing either corosync or dlm_controld is very unlikely help
   anything, and more likely to cause further problems, so it should
   be avoided as far as possible.

Apparently the problem started with corosync running correctly, but dlm_controld wasn't up; clvmd then blocked somewhere. I now have still four hosts with 60VMs or so to reboot. So any hint how to kill that lockspace is greatly appreciated.


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