connection manager really shouldn't' be used anymore for scaling. it hasn't been update in a long time, and doesn't support things like s2s. Id look at clustering using the cluster plugin.
I think the only real use case for connection manager anymore would be if you wanted proxy inbound internet client connections from the internet to a server that sits on the lan. for example, you might have the connection manager installed on the dmz accepting client connections, instead of having your openfire server which may sit on the lan, exposed directly to the internet.