[Linux-cluster] Tiebreaker IP

[Lon Hohberger]

On Fri, 2005-08-26 at 13:24 -0500, JACOB_LIBERMAN at Dell.com wrote:

> If it cant, it will assume its external interface is down
> and fence/reboot itself. The same holds true for nodeB. Unlike RHEL2.1
> which used STONITH, RHEL3 cluster nodes reboot themselves. 

Both use STONITH.  RHEL3 cluster nodes are more paranoid about running
without STONITH.

If STONITH is configured on a RHEL3 cluster, the node will instead wait
to be shot -- or for a new quorum to form -- if it loses network
connectivity.

> Anyway, I hope this answers your questions. It is fairly easy to test.
> Set up a 2 node cluster, then reboot the service owner. If the service
> starts on the other node, you should be configured correctly. Next
> disconnect the service owner from the network. The service owner should
> reboot itself with the watchdog or fail over the resource, depending on
> how its ocnfigured.

It should reboot itself because it loses quorum, really.  Basically,
without STONITH, a node thinks like this on RHEL3:

"I was quorate and now I'm not, and no one can cut me off from shared
storage... Uh, oh, REBOOT!"

(Note: On RHCS4/RHEL4, you *must* have I/O fencing (aka STONITH)
configured!)

-- Lon