A few months ago, I made a post talking about the new guide released by Microsoft for a DFS-R migration. I’ve gone through the guide and used it in my production environment to actually migrate my DC’s over to DFS-R. Here is a general rundown of what you can expect to see using excerpts from the white paper.
The migration process proceeds through a number of states, during which SYSVOL replication transitions from using File Replication Service (FRS) to using Distributed File System Replication (DFS Replication). This transition takes place in discrete steps, as described in the following sections.
You use the
dfsrmig command to migrate domain controllers from the Start state to each subsequent stable state until the domain controllers reach the Eliminated state. Before domain controllers migrate to the Eliminated state, you can reverse the migration if needed either completely back to the Start state or partially back to a previous stable transition state. This process is called rollback.
This picture shows the states through which the migration process moves. The large circles represent the four stable migration states. The small circles represent the transition states that a domain controller passes through to reach the stable states.
Migrating to the Prepared State
This migration phase includes the tasks in the following list. After this phase is complete, FRS will continue to replicate the SYSVOL shared folder that the domain uses, whereas DFS Replication replicates a copy of the SYSVOL folder.
dfsrmig /SetGlobalState 1command on the PDC emulator to start the migration to the Prepared state.
Before you continue the migration and migrate the domain to the Redirected state, it is important to first verify that the domain has properly migrated to the Prepared state.
On each domain controller in the domain that you want to migrate, open a command prompt window and type
net share to verify that the SYSVOL shared folder is shared by each domain controller in the domain and that this shared folder still maps to the SYSVOL folder that FRS is replicating.
Migrating to the Redirected State
After you have verified that all domain controllers have successfully migrated SYSVOL replication to the Prepared state and that SYSVOL replication still operates as expected, you can migrate SYSVOL replication to the Redirected state. In the Redirected state, DFS Replication takes over the replication of the primary SYSVOL folder for the domain; however, FRS continues to replicate the original SYSVOL folder.
dfsrmig /setglobalstate 2to set the global migration state to Redirected.
dfsrmig /getglobalstateto verify that the global migration state is Redirected.
Migrating to the Eliminated State
The final phase of the SYSVOL replication migration is migrating the domain to the Eliminated state. After you migrate SYSVOL replication to the Eliminated state, all SYSVOL replication duties are performed by DFS Replication and you can no longer roll back migration to a previous state.
dfsrmig /getmigrationstateto verify that all the domain controllers are at the Redirected state.
repadmin /ReplSumto verify that Active Directory replication is working properly. The output should indicate that there are no errors for any of the domain controllers in the domain.
dfsrmig /setglobalstate 3to set the global migration state to Eliminated.
dfsrmig /getglobalstateto verify that the global migration state is Eliminated.
dfsrmig /getmigrationstateto confirm that all domain controllers have reached the Eliminated state.
That’s all there is to the actual migration. I highly recommend going through all the steps rather than going from start straight to the eliminated state. This will ensure that you’re not going to have issues in the end. If you do run into any problems, just consult the Microsoft white paper.