On 09/01/2015 10:07 AM, Digimer wrote: > On 01/09/15 09:27 AM, Michael Schwartzkopff wrote: >> Hi, >> >> perhaps this question was answered elsewhere, but I count not find any >> satisfying answer. So is it possible to set uo a corosync/pacemaker cluster >> that detects errors and does the failover in a sub-second time span? >> >> if yes, how? >> >> >> Mit freundlichen Grüßen, >> >> Michael Schwartzkopff > > Corosync declares a loss of a node, so you would need to start by tuning > it (token loss timeout and loss count). Of course, as you tighten this > up, the chances of a transient issue causing false declaration of node > loss increases. > > Next, you'd need a fence device that can terminate and verify the node's > termination very, very quickly. I do not know of such a device. Part of > this is also the time taken for the fence agent to be invoked. > > Last, you'd need to have pacemaker calculate the new desired state and > make those changes. The services being recovered would need to start > exceptionally quickly. > > In theory, it's possible I suppose. In practice, very unlikely.
Another consideration: while pacemaker timeouts and intervals can be specified in milliseconds, internally pacemaker frequently truncates such values to whole seconds. I wouldn't recommend using anything less than 2s in any configured value. _______________________________________________ Users mailing list: [email protected] http://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
