[Linux-cluster] Fencing Problems

[Rich Edelman]

Ah, yes, I did set the two-node option to cman in
/etc/cluster/cluster.conf.

Perhaps some documentation should be updated... But would it not be
better to have some kind of timeout value on the nodes when trying to
fence the others? Seems to me that in a two-node scenario, if one node
is repeatedly trying to fence the other, and after say 10 tries it
can't, it should just give up and assume it is the problem node. Then,
hopefully, everything else would go quite well when that node came back.

Rich

-----Original Message-----
From: linux-cluster-bounces at redhat.com
[mailto:linux-cluster-bounces at redhat.com] On Behalf Of Patrick Caulfield
Sent: Tuesday, July 05, 2005 8:32 AM
To: linux clustering
Subject: Re: [Linux-cluster] Fencing Problems

Rich Edelman wrote:
> Hi all.
> 
> I've got a 2 node FC4 system here, connected via a Brocade FC switch 
> to FC SAN. I've followed usage.txt to a T, but seem to have some 
> fencing problems.
> 
> What happens is if one of the 2 nodes loses network connectivity, that

> node immediately gets fenced by the remaining node, which is all fine 
> and good. The problem here is the fenced node (the one without network
> connectivity) starts trying to fence the remaining node, and when 
> network connectivity is restored, succeeds in fencing the other node.
> Now both my nodes are fenced. And not only that, but I have the 'split

> brain' scenario, where each node thinks it is the only member of a 
> similarly named cluster.
> 
> Any ideas how to fix this?
> 

For a start you need to set the 2-node option to cman in the
/etc/cluster/cluster.conf file.

I think that 2-node option only works with power-switch fencing. It
relies on the fact that the two nodes will race to fence each other and
only the first one suceeds because the second is then dead.
-- 

patrick

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