Hello Anil, The size of the cluster does not really influence this, but downing it's members and partitions do.
In theory this problem can appear always when there is a "split brain" partition, meaning: when 2 clusters are formed - this is what happens in the above example. It would also happen if we replace the above problem with a partition that would force the cluster to form 2 separate clusters - ergo, again 2 cluster singletons would be running. Auto downing is the primary suspect in causing these unexpectedly, but there are other scenarios (I just imagined a horrible edge case of "partition between seed nodes during cluster starting"...). In general simply not using auto-downing with the cluster singleton will keep you out of trouble. You could also set the akka.cluster.min-nr-of-members = N, where N is the number of your *N*odes (3), so a restarted-lonely-partitioned-seedNode won't decide to become a cluster on it's own. This is described here http://doc.akka.io/docs/akka/snapshot/scala/cluster-usage.html#How_To_Startup_when_Cluster_Size_Reachedand it will make sure that the cluster won't "Up" members, until all members have joined - this will save us from spinning up the cluster singleton too early (and if a partition happens, you can. I personally think the ClusterSingleton is a nice tool, but it may seem a little bit* too tempting* to use and forget about the problematic cases. I've added some docs explaining this problem: https://github.com/akka/akka/commit/08fd4c93faac2d2aa625458090978723717a1864but I just noticed this is only on the master branch, thus it's not in the published 2.3.3 docs (will fix this for 2.3.4). -- Cheers, Konrad 'ktoso' Malawski hAkker - Typesafe, Inc <http://scaladays.org> -- >>>>>>>>>> Read the docs: http://akka.io/docs/ >>>>>>>>>> Check the FAQ: >>>>>>>>>> http://doc.akka.io/docs/akka/current/additional/faq.html >>>>>>>>>> Search the archives: https://groups.google.com/group/akka-user --- You received this message because you are subscribed to the Google Groups "Akka User List" group. To unsubscribe from this group and stop receiving emails from it, send an email to akka-user+unsubscr...@googlegroups.com. To post to this group, send email to akka-user@googlegroups.com. Visit this group at http://groups.google.com/group/akka-user. For more options, visit https://groups.google.com/d/optout.
