Our network has an Exchange 2010 installation ultilizing a DAG. The DAG has one DB copied between three servers. All three of these same servers host Mailbox, Transport, and the CAS roles.
One thing that's not clear to me is the relationship between the Failover Cluster Manager, the DAG, and the non mailbox roles. Obviosuly the activiation preference and other parameters control which server has the active copy of the DB, but what server has the active CAS and Transport role when NLB or an array is not in play for those roles?
Is if the same server that is currently hosting the active mail DB?