[Pacemaker] newbie question(s)

Florian Crouzat gentoo at floriancrouzat.net
Thu May 23 04:27:25 EDT 2013

Le 22/05/2013 02:13, Alex Samad - Yieldbroker a écrit :
>>> > >Any help or suggestions muchly appreciated
>>> > >
>> >
>> >Also, fencing!
> Not sure that I need it. The app is always running on both nodes, it's just the ip address that is shared

A cluster without fencing is not a cluster, by definition. Proper 
fencing should be at least two different methods, eg: IPMI + PDU.

Some peoples live with clusters without fencing, they mostly rely on 
luck  and luck is not very "High Availability".

If you want a proof that you need it, just drop all corosync network 
traffic => split brain, you have two masters on your network until an 
admin fixes it.

You could also wait for a failover where the VIP or (any resource) will 
fail to properly stop, the cluster doesn't know what do to on 
stop-failures (beside fencing), it freezes in this weird state => you 
have two slaves on your network until an admin fixes it.

Florian Crouzat

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