ejabberd Community edition can only run in a local cluster. It requires low latency high reliability network between all the nodes in the cluster.
ejabberd Business edition can be configured to run in multiple data-centers and multiple regions across the world.
The main benefits of those features are:
- Better reliability and resistance to failure. The service will remain available in case of complete failure of a data center.
- Better service for the users, as the closest geographical data center can be use to connect.
- Better resistance and recovery from networking problems like netsplit. It makes administration of ejabberd cluster much easier and requires much less maintenance.