Any advice on how to handle fail-over in an ejabberd cluster?

Context:

I have a system that will need to support 20,000 connected chat users spread over 100 chat rooms. During performance testing I've found that I can get up to 6,000 connected users on a single box before I get a crash dump, so in production I'll probably go with four servers in a cluster.

My Question:

I understand that a chatroom is bound to a server node, so that if the node dies the chatroom disappears with it and the users no longer belong to the room. Is there a way to "replicate" a chatroom over to another node so that users who are left behind are moved to the replicated开发者_运维知识库 room? If not, what do you do to keep continuity for the users?

What hardware are you using ? 6000 connected users seem a bit low. Also, ejabberd is not supposed to crash under load. It might slow down, but not crash.

There is something wrong in your setup.

About replicating a chatroom node, it's not easy. It's better to handle smooth reconnection on the client side.

But then again, ejabberd should not crash under this kind of load, unless something's wrong.