On 25/07/2013, at 4:31 PM, Devdas Bhagat <devdas.bha...@booking.com> wrote:
> We have a master-slave setup for Redis, running 6 instances of Redis on > each physical host, and one floating IP between them. > > Each redis instance is part of a single group. > > When we fail over the IP in production, I'm observing this sequence of > events: > Pacemaker brings down the floating IP > Pacemaker demotes the master redis instance > Pacemaker stops each running redis process in sequence (essentially > stopping the group) > Pacemaker promotes the slave > Pacemaker brings up the floating IP on the former slave > > (This follows documented behaviour as I understand it, see > http://www.mail-archive.com/pacemaker@oss.clusterlabs.org/msg05344.html > for someone else with a similar problem). > > Under production traffic load, each redis process takes about 4 to 5 > seconds to sync to disk and cleanup. Can they be stopped and/or started in parallel? If so, don't put them in a group - problem solved > This means that a simple failover > takes between 24 and 30 seconds, which is a bit too long for us. > Acceptable failover times would be less than 5 seconds (the lower the > better). > > Is there a configuration option to change the failover process to *not* > stop the group before promoting the secondary? Alternatively, > suggestions on how to get pacemaker to manage only the state of the > redis process but not the process itself are welcome (A process failure > can be diagnosed by monitoring the response or lack thereof from redis > itself, so a dead or non responding process can be treated alike as far > as monitoring it goes). > > Devdas Bhagat > > _______________________________________________ > Pacemaker mailing list: Pacemaker@oss.clusterlabs.org > http://oss.clusterlabs.org/mailman/listinfo/pacemaker > > Project Home: http://www.clusterlabs.org > Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf > Bugs: http://bugs.clusterlabs.org _______________________________________________ Pacemaker mailing list: Pacemaker@oss.clusterlabs.org http://oss.clusterlabs.org/mailman/listinfo/pacemaker Project Home: http://www.clusterlabs.org Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf Bugs: http://bugs.clusterlabs.org
