Revisiting Database Availability Groups
Despite the obvious change in configuring a DAG through the Exchange Admin Center versus using the old Exchange Management Console, configuring a DAG in Exchange 2013 is virtually the same as in 2010. However, some improvements have been introduced to this technology, which is worth covering here.
Note that both Exchange 2013 Standard and Enterprise features can be used for DAGs and that a DAG can contain a mix of both. However, each DAG member must be running the exact same operating system, either Windows Server 2008 R2 or Windows Server 2012.
Best copy selection changes
A critical component of any DAG is Active Manager, part of the Microsoft Exchange Replication service, which runs on all Mailbox servers ...