[Linux-HA] Antw: Single Point of Failure
Ulrich.Windl at rz.uni-regensburg.de
Fri Jan 13 00:52:08 MST 2012
>>> "Paul O'Rorke" <paul at paulororke.net> schrieb am 12.01.2012 um 21:20 in
<CADinG56TMJU1Gb9Zw3JkdcKh=v3ms--+0DmTraX8CD9WtkHt3Q at mail.gmail.com>:
> 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
E-Mail always had a failover concept independent of clusters: It's called "MX records". Agreed, MX records help you to receive mail for you, but it may not help you to actually deliver the messages to the local recipient.
> 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.
You could also use a load balancer for the MTA, or use a "floating IP-Address" for the MTA (which the Linux cluster would support). However you'll have to take care that your configuration files on the cluster nodes are at least consistent (if not even equal).
> What am I missing?
> Please and thanks
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