Re: [wildfly-dev] Is there a way to avoid multiple singleton masters

WFLY-68 adds the ability to specify a quorum required for a singleton service to start, i.e. a partition must have at least Q members in order for a singleton master election to take place. In general, the quorum value should be int(N/2)+1, where N is the cluster size. e.g. If your cluster size is 3, it would be advisable to set the quorum size to 2. You can find an example of building a singleton service with a specified quorum here: https://github.com/wildfly/wildfly/blob/master/testsuite/integration/clus... This of course means that any partition that does not have a least Q members will not have a transaction recovery manager until the partition is healed. ----- Original Message ----- > From: "Michael Musgrove" <mmusgrov(a)redhat.com&gt; > To: wildfly-dev(a)lists.jboss.org > Sent: Wednesday, June 18, 2014 10:12:31 AM > Subject: [wildfly-dev] Is there a way to avoid multiple singleton masters > > I'd like to have an option of running our transaction recovery manager > as an HA singleton. WFLY-68 implies that the master can run at most once > (even in the presences of network partition) but I don't see how we can > guarantee that. If I hold the service start in a breakpoint then split > the network and then allow another master on the other side of the > partition to become master and then release the breakpoint we will > briefly have two services running. I know using breakpoints is invalid > but surely there are timing windows where the same outcome could > conceivably occur. > > Mike > > -- > Michael Musgrove > Transactions Team > e: mmusgrov(a)redhat.com > t: +44 191 243 0870 > > Registered in England and Wales under Company Registration No. 03798903 > Directors: Michael Cunningham (US), Charles Peters (US), Matt Parson (US), > Michael O'Neill(Ireland) > > _______________________________________________ > wildfly-dev mailing list > wildfly-dev(a)lists.jboss.org > https://lists.jboss.org/mailman/listinfo/wildfly-dev >