On Mon, 2021-07-26 at 12:21 -0400, john tillman wrote: > > On Mon, Jul 26, 2021 at 4:53 PM john tillman <jo...@panix.com> > > wrote: > > > > > > > > > > Maybe explain how it should work: > > > > > If the two nodes cannot rech each other, but each can reach > > > > > the ping > > > > > node, > > > > > which node has the quorum then? > > > > > > > > > > > > > Guess both - which is what is played down as 'disadvantage' in > > > > the > > > > description > > > > below ;-) > > > > > > > > > > > > > > It is not perfect, I agree, but it may be better than nothing at > > > all. > > > > > > As for how it worked in my head: > > > > > > I would have used the switch's IP address as the "ping" tie > > > breaker; a > > > common connection point between the two nodes. My assumption is > > > that if > > > there was network loss by Node A then it would lose quorum. In > > > the mean > > > time Node B would still reach the switch, achieve quorum, and > > > start/move > > > resources. > > > > > > > You seriously misunderstand what "split brain" means. Once more - > > both > > nodes are up, neither node can contact another node, both nodes can > > ping switch. What should each node do now? > > _______________________________________________ > > Manage your subscription: > > https://lists.clusterlabs.org/mailman/listinfo/users > > > > ClusterLabs home: https://www.clusterlabs.org/ > > > > > > > They would continue running their resources and we would have split > brain. > > So there is no safe way to support a two node cluster 100% of the > time. > But when all you have are two nodes and a switch ... well, when life
If it's an intelligent (SNMP-managed) switch, you could use the fence_ifmib agent to fence a node by cutting off its network access (which is safe if the node doesn't have access to a shared resource such as a disk by means other than the network being cut off). > gives > you lemons ... > > Thank you again for the response and I apologize for beating a dead > horse > here. > -- Ken Gaillot <kgail...@redhat.com> _______________________________________________ Manage your subscription: https://lists.clusterlabs.org/mailman/listinfo/users ClusterLabs home: https://www.clusterlabs.org/
