[ClusterLabs] OCFS2 on cLVM with node waiting for fencing timeout

Eric Ren zren at suse.com
Thu Oct 13 03:31:01 EDT 2016


On 10/10/2016 10:46 PM, Ulrich Windl wrote:
> Hi!
> I observed an interesting thing: In a three node cluster (SLES11 SP4) with cLVM and OCFS2 on top, one node was fenced as the OCFS2 filesystem was somehow busy on unmount. We have (for paranoid reasons mainly) an excessive long fencing timout for SBD: 180 seconds
> While one node was actually reset immediately (the cluster was still waiting for the fencing to "complete" through timeout), the other nodes seemed to freeze the filesystem. Thus I observed a read delay > 140 seconds on one node, the other was also close to 140 seconds.
ocfs2 and cLVM are both depending on DLM. DLM deamon will notify them to stop service (which 
means any cluster locking
request would be blocked) during the fencing process.

So I'm wondering why it takes so long to finish the fencing process?

> This was not expected for a cluster filesystem (by me).
> I wonder: Is that expected bahavior?
> Regards,
> Ulrich
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