[Info-vax] set cluster/expected_votes
Malcolm Dunnett
nothome at spammers.are.scum
Tue Aug 11 22:59:12 EDT 2009
JF Mezei wrote:
> Malcolm Dunnett wrote:
>
>> What it does is tells the other nodes to recompute quorum based on the
>> votes remaining in the cluster. I don't know if you consider this "much"
>> or not, but it would seem to be precisely what is needed in this situation.
>
> It won't magically allow a cluster to continue to operate with fewer
> nodes than it had been designed to operate. AKA: you cannot cheat the
> minimums set by the sysgen expected_votes if I remember correctly.
>
Of course it will (well not magically - it's by design). There is no
"number of nodes the cluster has been designated to operate with" - it's
a dynamic value based the nodes in the cluster. The required number of
votes is always adjusted upwards as needed when a node joins the cluster
- downward adjustments are not automatic - that's what REMOVE NODE is for.
Are you perhaps thinking of the SYSGEN parameter EXPECTED_VOTES? This
parameter is only significant during boot time - a node will not boot if
it can't join a cluster with EXPECTED_VOTES votes. Once a node is
running the SYSGEN parameter has no effect.
Can you elaborate on the situation in which this won't work?
I've used it to take a 5 vote (2+2+1) cluster down to 1 vote with no
problem. From reading the description I can't see where it could be a
problem - quorum is adjusted to reflect the number of votes remaining in
the cluster.
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