I recently upgraded from Exchange 2003 to 2010. Phase one was completed about a month ago (single server, 150 mailboxes) and went very well. Phase two is designed to introduce a manual DNS failover option using a datacenter where the second Exchange server is installed and connected back to the main office over a Cisco VPN.
I had installed the OS (2008R2) and the new Exchange server at the datacenter a couple of days ago and yesterday got around to fixing a routing issue between the two servers. Within minutes of being able to communicate with each other email services stopped working. I was not aware that by installing another Exchange instance that it would immediately attempt to use the new server to process emails. The new instance of Exchange hadn't been configured yet and so naturally it wasn't working properly. This is where I really could use some help.
My plan is to add a secondary MX record and if the primary site fails email would then be delivered to the server over at the datacenter. Based on what I have read I'll need to setup a DAG, DAC, witness server, and preferably another domain controller at the datacenter. I was also told that I'm in for a lot of work to fix the CAS array since I didn't configure it with the other site in mind from the beginning.
How can I go about adding the additional services and configuring the server without causing the same email problems from yesterday? I feel that as soon as I power it back on I'll get the same problem. I'm also very interested in any information on how I can make the CAS array changes needed to make the clients work when the server fails over. Any info you could provide would be very much appreciated!
Dan