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Re: [Xen-users] How can I do HA among dom0s?

To: John Madden <jmadden@xxxxxxxxxxx>
Subject: Re: [Xen-users] How can I do HA among dom0s?
From: Miguel Araujo <maraujo@xxxxxxxxx>
Date: Fri, 30 Nov 2007 15:32:34 +0100
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John Madden escribió:
I need some sort of daemon that detects if the other host is down and let me execute a custom script to live migrate machines. Heartbeat, Keepalive or ucarp, as far as I know, don't do this. They first detect when the host is down and after they activate a virtual IP address. If the service that they make HA is stateless, let's say DNS, you don't need to do any syncing between disk, if it is a Database you have to do DRBD.

Heartbeat *does* allow scripting -- in fact, its entire HA
startup/shutdown is shell script-based.  You can do about anything you
want with heartbeat and a little creativity.
DRDB is not sufficient for database mirroring.  DRDB is not, in and of
itself, a HA/clustering solution; all it does is disk mirroring.

In the event of a dom0 failure, you can assume your domU's have failed.
STONITH the downed dom0, set up the storage on the backup dom0 machine,
start up the domU's.


Thanks both for your answers,

Sorry, but I did not find any about running shell scripts from Hearbeat, I will keep reading about it (I must have jump it), thanks for the advice. Also I'm going to read your link António.

I know what DRBD does, what I was saying is that if I don't have a way to synchronize data between nodes (let's say DRBD) it would be impossible to make heartbeat with a stateful service. I know you still loose your RAM if the master node crashes. For sure, DRBD it is not an HA solution, for that you would need DRBD (or other way) + Heartbeating.

Thanks a lot,


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