[Linux-cluster] Quorum question

Patrick Caulfield pcaulfie at redhat.com
Wed Dec 21 14:10:24 UTC 2005

Bowie Bailey wrote:
> Patrick Caulfield <mailto:pcaulfie at redhat.com> wrote:

>>No, because fencing has to be done by one of the cluster nodes. And
>>the cluster must be quorate to fence another node - otherwise it
>>could be an isolated node fencing the valid part.
> Ok, that makes sense.  How does this work with a two-node cluster?

It's a race to see who gets fenced first. The winner lives :)

>>>What I will have is three nodes.  Two that actively use the data in
>>>the shared storage and one node that handles backups.
>>>The backup node is not critical and could be down at any time for a
>>>number of reasons.  I want to make sure that if the backup node is
>>>down and one of the other nodes crashes, that the one remaining
>>>node will continue to be able to access the data in the GFS.

Not really. What you seem to want is a two-node cluster with a zero-vote
"hanger-on" node. cman is either a two-node cluster or not, there's no way to
tell it that the backup node isn't important.

I think the think to do it is not to have the backup node in the cluster at
all and think of sme other way of doing the backups - NFS say.



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