[Linux-cluster] 2-node cluster and fence_drac

[Lon Hohberger]

On Mon, 2006-08-07 at 15:21 -0500, hai wu wrote:
> Hi,
> For a 2-node cluster (RHEL4), does it require the use of power switch
> or fence_drac would be good enough for the setup? Would fence_drac
> work properly in a 2-node cluster?
> Thanks,
> Hai

fence_drac would be fine, but you need to understand that with DRAC (or
any integrated power management which receives power from the machine)
that if host power is completely lost, fencing will fail - causing the
cluster to stop.

This failure is indistinguishable from DRAC + host losing network at the
same time (ex: the ethernet switch fails).

Generally, these machines have redundant power, so losing power all at
once is less likely.

So, DRAC is fine, but there are failure cases where it is less than
optimal, particularly in machines without redundant power supplies.

-- Lon