I have a two-node DRBD 9 resource configured in Primary-Secondary mode with automatic failover configured with Pacemaker.
I know that I need to configure STONITH in Pacemaker and then set DRBD's fencing to "resource-and-stonith". The nodes are Supermicro servers with IPMI. I'm planning to use IPMI for my (first) fencing level. Where I'm confused is regarding whether I must have a second fencing level beyond IPMI? Or will DRBD's fencing configuration, combined with IPMI be good enough? Looking at: http://clusterlabs.org/pacemaker/doc/en-US/Pacemaker/1.1/pdf/Clusters_from_Scratch/Pacemaker-1.1-Clusters_from_Scratch-en-US.pdf It reads: "A common mistake people make when choosing a STONITH device is to use a remote power switch (such as many on-board IPMI controllers) that shares power with the node it controls. If the power fails in such a case, the cluster cannot be sure whether the node is really offline, or active and suffering from a network fault, so the cluster will stop all resources to avoid a possible split-brain situation." I don't understand this. If the power fails to a node, then won't the node, by definition be down (since there is no power going to the node)? So, how then could there be a split brain when one node has no power? Is the above quote stating that if Pacemaker can't confirm that one node has been STONITHed, that it won't allow the remaining node to work, either? Thanks! Bryan Walton _______________________________________________ drbd-user mailing list [email protected] http://lists.linbit.com/mailman/listinfo/drbd-user
