I am setting up a Unity 7.X Voice Mail-only, with Failover deployment. They do not have Exchange in their environemnt so I will be placing Exchange on the Unity server(s). I'm looking at the procedure on CCO and it implies (or I read it as) that the full version of Exchange goes on the secondary server and Administration software for Exchange goes on the primary. So the message store only exists on the secondary/failover? I'm quite confused as to what components go on which servers, and how redundant the end-product is going/suppossed to be.
Also, the general procedure implies that the Failover server should be installed first, is that correct?