Domain controllers

Failover of domain controllers is dependent on the Double-Take Availability functionality you are using.

Domain controller role—If you want to failover a domain controller, including the roles of the domain controller, you should create full-server or virtual workload protection.
Non-domain controller role—If you are only protecting data, you can failover a domain controller, but the roles of the domain controller are not included. The server will be a member server after failover. In this case, you need to keep in mind that the unavailability of some of the FSMO (Flexible Single Master Operation) roles can cause immediate issues such as the inability to extend the Active Directory schema or to add a domain to a forest.
Global catalog server—If your source is a global catalog server, you should have other global catalog servers throughout the network to ensure that the failure of the source will not impact users.