I have two Server 2012 Domain Controllers.  Each has DNS and DHCP with failover.  The NIC properties of each server have the primary DNS pointing to the other server and the secondary DNS pointing to itself (127.0.0.1).

DC1 is a virtual machine on Hyper-V.  It holds the Schema Master, Domain Naming Master, PDC Master, RID Pool Manager and Infrastructure Master roles.  DC1 is also the time DC.  Both DCs are Global Catalogs.  DC2 is a physical server.  Should I move the roles to the physical server?

I'm wondering because the power will be shutting off for several hours and I was thinking about boot order when the power returns.  I can't start DC1 until the hypervisor gets started.  The hypervisor won't authenticate on the network until a DC is running.  I can start DC2 first but in the past I noticed that devices take a long time to logon when DC1 is down...since it is holding all the roles.

Hi

 The important point is MS do not Support combining AD DS role and the failover cluster feature in Wndows 2012 anymore.

Check this detailed information

https://social.technet.microsoft.com/Forums/en-US/b4e56e1f-6f0e-4183-895f-f5a30694aaf1/dhcp-migration-2003-r2-to-2012-r2?forum=winserverMigration

 i recommend that you could migrate dhcp role to member servers and then configure these 2 member dhcp server to failover cluster.

Also i always prefer that all fsmo roles on a DC and it is be a physcial server.(cause of domain restore scenario(bare metal recovery).