On Feb 10, 2009, at 4:19 AM, Philip Pinto wrote:
Well one other reason you may want a two node cluster would be
running under
a virtualization engine - VMware or z/VM - just to refrain from
wasting
hypervisor resources
Thats a pretty poor reason.
A minimal third node that does nothing but vote in elections is going
to be swapped to disk for most of its life and consume very little CPU/
RAM.
- all of the clusters we run are two node clusters for
this reason - and HA is the only solution we have to allow for
monitoring
and restarting failed resources. We do automatically restart fenced
nodes
in the event of a failure. Last time I checked I was sane - at
least that's
what I keep telling myself ;-)
It will work fine right up until the point at which you get a
persistent failure (one not solved by a reboot).
At which point you'll go into a STONITH loop with each node coming up
and shooting the other over and over again until you resolve the
underlying issue.
Being VMs, that might reduce the chance of a persistent failure, but
the possibility is still there.
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