Is the Ejabberd default DB suited for large cluster deployments?

Question

1. Im setting up a cluster of Ejabberd nodes to to host 1M+ active connections.

Is the internal Mnesia database on every cluster the best solution in terms of reliability and load balancing, or would it be better to use an external DB on a seperate server?

2. From what I can tell, each node needs its own DB and all nodes cant share one common DB?

Answer 1

My instinct of scaling systems generally says that a cluster of external databases would be a better thing than having lots of internal databases. I've never actually looked at scaling ejabberd, but generally it's good to separate services into clusters.

This quora answer seems to agree about scaling to a separate DB when you've many nodes.