ejabberd cluster: Multi-master or Master-slave

Question

So far what I've come across is this -

1. Setting up ejabberd cluster in a master-slave configuration, there would be a single point of failure and people have experienced issues when even after fixing the master (if it goes down), the cluster doesn't become operable again. Also sometimes, ejabberd instances of every slave would have to be revisited again to get them working properly, or mnesia commands would have to be in-putted again to make master communicate with the slaves.
2. Setting up ejabberd cluster in a multi-master configuration then any of the nodes can be taken out of the cluster without bringing the whole cluster down. Basically, there is no single point of failure and, this is also the way in which the official documentation for ejabberd tells you to do via the join_cluster argument they expose in the ejabberdctl script. HOWEVER, in this case, all the data is replicated across both nodes which is a big performance overhead in my opinion.

So it boils down to this.

What is the best/recommended/popular mode in which an ejabberd cluster of 2 nodes should be set up mostly with respect to performance but keeping other critical factors (fault tolerance, load balancing) in mind as well.

Answer 1

There is only a single mode in ejabberd. Basically, it works like what you describe as multi-master. master-slave would basically be the same setup without any traffic sent to the second node by load balancing mechanism.

So case 2 is the way to go.