We're currently running SBS 2011 for our AD domain controller (no Exchange) and looking at our options for moving to Server 2012 R2 Essentials.
I understand that Windows Server 2012 R2 Essentials must be the domain controller at the root of the Active Directory Forest and must hold all the FSMO roles.
How do we implement fault tolerance with this approach?
Can we setup a Windows Server 2012 R2 Standard machine and configure it as a replica DC?
How do the CALs work in this scenario since Essentials does not require CALs but Standard does?