We have 2 locations connected via site-to-site VPN. Internet speed is about 3MB, ping times between locations is about 70ms. They are currently in separate Active Directory sites, separate subnets, but one domain. We want to have Exchange in failover mode and would prefer not to have to go through the manual failover process if we don't have to. What would be the pros and cons, and the process to merge the sites if the pros outweigh?
The forest is native mode, 2003 R2 DC in 1 location and 2008 R2 DC in the other. We are adding a 2012 server to the first location and Exchange 2013. I understand with 1 site we need a member server to act as a DAG witness.