I am currently running Exchange 2010 with a DAG and 4 Exchange servers (this will be changing soon). I have a DAG running on an active and a passive node (one of the other Exchange servers is for my China office and the other is basically doing nothing - it's a VM that will be decommissioned soon). I have a new physical Exchange server that I brought online (as a CAS-Hub) and, of course, mail stopped working because the Exchange forest is trying to use the new server. So I shut that machine down until I was ready to migrate. What I need to do needs to be done with the least amount of down-time possible. What I'd LIKE to do, is be able to bring the new Exchange server up and just keep traffic flowing as is (for the meantime), join the new Exchange server to the DAG and let the databases replicate to that box. Once the replication is complete, I would like to evict the current primary from the DAG, then make the necessary changes in my firewall, and bring the new server online as the primary Exchange server. I will need to replicate all the send/receive connectors, and I already have the new certificate in place that includes the new server name. I will also have to change autodiscover settings to ensure my Outlook anywhere clients can point to the new server and the internal URL changes properly, as well as my owa URL. My questions are:
1. What can I do to bring the new Exchange server online without an email outage?
2. Is joining the new server to the DAG and replicating them the quickest, easiest way to get the databases to the new server without down-time?
3. Did I miss anything above in my checklist for moving to the new server as the primary?
4. When I move to the new server, what is the easiest way to point the Outlook clients to the new box? I will have autodiscover configured to use the new server, but this, I believe, will require manual intervention.
If I need to clarify anything, I'll be happy to. As always, any help would be appreciated. Thanks in advance.