[Linux-cluster] Rhcs4 split brain prolem with single heartbeat cable ?

[Lon Hohberger]

On Thu, 2005-09-01 at 06:47 +0000, nattapon viroonsri wrote:
> >From config menu in Rhcs4 look like dont require share storage to store 
> quorum partion and no ip tie-breaker to config.
> And  i use only 1 network cable both for client access resource and 
> heartbeat channel.
> So  if one node have problem with network connection. the backup node can 
> provide service with uninterrupt.
> But Can split brain will occur ?
> Can both node issue i/o to share at the same time ?
> 
> So hould i use 2 heartbeat channel ?
> If i use 2 heartbeat connection how can i detect fail of network connection 
> for client access resource ( no  ip tie-breaker to config in rhcs4) ?

CMAN (the cluster manager) ensures no split brain via fencing:  If you
have two nodes and disconnect the cable on one of them, the remaining
(connected) node will fence the node which was disconnected.

To use it, you need two_node=1 and expected_votes=1 in cluster.conf
(which system-config-cluster correctly sets up for you).

As stated previously: Fencing hardware is *required* for RHCS4.

-- Lon