[Pacemaker] OCFS2 problems when connectivity lost

Ivan Savčić | Epix ivan.savcic at epix.rs
Wed Dec 21 05:47:43 EST 2011


We are having a problem with a 3-node cluster based on 
Pacemaker/Corosync with 2 primary DRBD+OCFS2 nodes and a quorum node.

Nodes run on Debian Squeeze, all packages are from the stable branch 
except for Corosync (which is from backports for udpu functionality). 
Each node has a single network card.

When the network is up, everything works without any problems, graceful 
shutdown of resources on any node works as intended and doesn't reflect 
on the remaining cluster partition.

When the network is down on one OCFS2 node, Pacemaker 
(no-quorum-policy="stop") tries to shut the resources down on that node, 
but fails to stop the OCFS2 filesystem resource stating that it is "in use".

*Both* OCFS2 nodes (ie. the one with the network down and the one which 
is still up in the partition with quorum) hang with dmesg reporting that 
events, ocfs2rec and ocfs2_wq are "blocked for more than 120 seconds".

When the network is operational, umount by hand works without any 
problems, because for the testing scenario there are no services running 
which are keeping the mountpoint busy.

Configuration we used is pretty much from "ClusterStack/LucidTesting" 
document [1], with clone-max="2" added where needed because of the 
additional quorum node in comparison to that document.

NB: we have successfully reproduced this problem on three Ubuntu 11.10 
Server nodes as well.

Any ideas?

PS: I am aware that this is not an OCFS2 mailing list, but I hope that 
someone here encountered this problem as well and can give us some 
insight on it...




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