AW: startup of resource groups with one node down

"Martin Bene" <[email protected]> Tue, 7 May 2002 21:43:38 +0200
Newsgroups gmane.linux.failsafe
Message-ID <[email protected]>
> this is not true. membership can form even if the tiebreaker 
> node is not available. In a 2 node cluster with network partition, 
> if the tiebreaker node is not able to reset the non-tiebreaker 
> node and non-tiebreaker node can successfully reset
> the tiebreaker node, a membership of one node (non-tiebreaker node)
> can be formed.

The above is what I've observed when I start out with the cluster with ha services running on both nodes and then partition the network or power one of them down. 

On startup however, it's not what I'm observing. if the tiebreaker node is not available (switched off), the available node neither tries to reset the tiebreaker, nor does it form a memership, at least not in the time I've given it to try. (~ 30 minutes). cmsd exits with "Cmsd is out of membership, will restart after notifying clients" after trying to reach the offline node for 30 seconds, and gets restarted by cmond. repeat indefinitely.

>> That said, I still don't understand where the first case 
>> differs from starting up with both nodes present and then 
>> loosing one :-)
> 
> The key difference is in the second case, you are making an 
> assumption that there are no HA resources running on the node 
> (which is hopefully down).

The differnce in the second case is clear, what still makes me wonder is that the cluster ends up in different states when I
	1) start ha services with two nodes, switch one off after sucessfull startup
	2) start ha services for whole cluster (not just for available node) with just one node available.

Both scenarios end up with one node in UP and one node (after being reset) in DOWN status; cluster in "online with error" status. I'd have assumed the cluster state of these two cases to be functionaly equivalent now, but it isn't: in case 1) resource groups can be brought on/offline without problems, in case 2) they can't. Seems rather strange to me.

Bye, Martin