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

[Miguel Araujo <maraujo@xxxxxxxxx>]

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.
>
> John
>
>   
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,

      Miguel



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