[Linux-cluster] question about what happens when fencing fails

[Lon Hohberger]

On Fri, 2008-06-20 at 14:56 +0930, David Monro wrote:

> The most likely failure scenario for us at the moment is complete loss
> of the ethernet network between the 2 sites, with the SAN remaining up.
> Obviously in this case both nodes will be unable to see the other, and
> in addition will be unable to fence each other.

That's unfortunate. ;)

> In the case where I do not use a quorum disk, what will happen? I would
> have to guess that the answer will be a dead cluster, since neither node
> can succeed at fencing the other.

Correct.

> In the case where I do use a quorum disk, what will happen?

Well, since fencing is required when using a quorum disk, the effect
will be the same.

The quorum disk can be used to help decide *who* is allowed to fence.

> I did look at other fencing options as well, but I can't use fence_scsi
> (because we use dm_multipath - a pity because its about the one thing
> which actually should work for this scenario I think!), or fence_brocade
> (because the node can't get to the ethernet port on the switch in the
> other site).

That should be fixed in 5.2 (I think?)

-- Lon