(This is a question more about Server versions than Exchange, but will provide a bit of background just to give the picture.)
This is the current setup: We have two Exch 2010 servers. One in Location A, the other in B. A would be the 'primary' site, as it has all the connectors, etc. to receive the mail, and B is functioning simply as a mailbox server.
We want to upgrade the setup so it will be DAG setup.
Our first big concern is that you need Server Enterprise on both boxes. Currently they both have Server 2008 Standard.
Server 2008 Enterprise is EOL, and not available through channels. HOWEVER, you can still source it from places that sell older versions, etc. so we will assume I can get.
Would it work to just get 2008 Ent, and do an in-place (so to speak) upgrade? How would this work for CALs?