[Linux-HA] Single Point of Failure

[Paul O'Rorke]

Please excuse me if this is documented and I failed to find it.  I have
been investigating ha-linux to provide Business Continuity in our mail
server.  Currently we have a single mail server in our main office.  We
would like to set up a second server in a geographically different location
and make a cluster of 2 nodes so that we can continue doing business if one
fails.

As far as I can tell ha-linux with Pacemaker is ideally suited to this.  My
question is around how the cluster handles requests to the mail server(s).
Can anyone suggest some appropriate reading for where/how this is
handled?   My concern is that should there be a failure at the location
that is receiving the requests how does it know to use the second node?  Is
this typically done through zone files and an priority?  Obviously I am
missing some important reading here because it would seem to me that there
could still be a single point of failure and that doesn't seem right.

What am I missing?

Please and thanks

-- 
Paul O'Rorke