On 02/13/2018 01:28 PM, Maxim wrote: > 13.02.2018 14:03, Klaus Wenninger пишет: >> - fencing helps you turning the 'maybe the node is down - it doesn't > > respond within x milli-seconds' into certainty that your node is dead > > and won't interfere with the rest of the cluster > > > > Regards, Klaus > > It is clear. But will it force pacemaker to perceive that the node is > down faster?
Let's put that differently. With fencing you can make the loss-detection more aggressive and thus more prone to false-positives without risking a split-brain situation. (Actually without fencing you can never be really sure if the other side is really gone!) But to be honest if you are really behind sub-second detection/switchover I'm not sure if fencing - at least with the current implementation in pacemaker and the current selection of fencing-devices - will give you satisfactory results. > [Unfortunatly, I've no a hardware that implements fencing abilities > nearby and can't try it myself] If you don't have any of the usual fencing-devices available you might have some kind of a shared-disk that might be usable with SBD. For a 2-node-cluster with a single shared-disk (as in your case if I got it correctly) assure to pick an SBD-version that has https://github.com/ClusterLabs/sbd/commit/4bd0a66da3ac9c9afaeb8a2468cdd3ed51ad3377. But again I doubt that this will work reliably with sub-second requirements. > > [Seems, it is the last question from my side that is devoted to this > topic] > > Thank you and Ken for the participation! > > Regards, > Maxim Not saying I'm not interested in experiences/requirements with pacemaker doing failovers in a sub-second or more relaxed low-single-digit-second timeframe. Seeing this working reliably would open up pacemaker for a completely new class of applications. Regards, Klaus _______________________________________________ Users mailing list: Users@clusterlabs.org http://lists.clusterlabs.org/mailman/listinfo/users Project Home: http://www.clusterlabs.org Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf Bugs: http://bugs.clusterlabs.org