We're revisiting zimbra once again but I wanted to see how others are implementing hot fail over and load balancing. We are currently running kerio because it supports true hot fail over. Without getting into a lot of useless talk I will simply ask...

What is the preferred way to setup a load balanced zimbra cluster with hot fail over? When I say hot fail over I mean if one of the servers in the cluster goes down there is no interruption in service to any user. By load balancing I mean no one server will be overloaded with users and it does not require manually balancing new account creation across the cluster.

Any and all input is appreciated.