How to Migrate SYSVOL replication to DFS replication

Summary
It was time to migrate SYSVOL replication to DFS replication.

One division could deploy another server; it could be the Windows Server 2003 machine to not a domain controller anymore.


How-to
1. The machine running Windows Server 2003 not to be a Domain Controller.


2. DFS: Only on domain controllers operating in the Windows Server 2008 domain functional level.
 
2.1.
Run Active Directory Domains and Trusts
  • Raise Domain Functional Level
  • Raise Forest Functional Level


2.2.
Run as administrator to check state ready or not:
Case-A:
PS C:\Windows\system32> dfsrmig /GetGlobalState

DFSR migration has not yet initialized. To start migration please set global state to desired value.

Case-B:
PS C:\Windows\system32> dfsrmig /GetGlobalState
 
The current domain functional level is not Windows Server 2008 or above.
DFSRMig is only supported on Windows Server 2008 or above level domains.

 
3.
PS C:\Windows\system32> dfsrmig /SetGlobalState 1

Current DFSR global state: 'Start'
New DFSR global state: 'Prepared'

Migration will proceed to 'Prepared' state. DFSR service will
copy the contents of SYSVOL to SYSVOL_DFSR
folder.

If any DC is unable to start migration then try manual polling.
OR Run with option /CreateGlobalObjects.
Migration can start anytime between 15 min to 1 hour.
Succeeded.


4. On the Primary Domain Controller
PS C:\Windows\system32> dfsrmig /GetGlobalState

Current DFSR global state: 'Prepared'
Succeeded.

 
5. Check Domain Controllers
PS C:\Windows\system32> dfsrmig /GetMigrationState

The following Domain Controllers are not in sync with Global state ('Prepared'):

Domain Controller (Local Migration State) - DC Type
===================================================
 
DC02 ('Waiting For Initial Sync') - Writable DC

Migration has not yet reached a consistent state on all Domain Controllers.
State information might be stale due to AD latency.

5.1
PS C:\Windows\system32> dfsrmig /GetMigrationState

All Domain Controllers have migrated successfully to Global state ('Prepared').
Migration has reached a consistent state on all Domain Controllers.
Succeeded.


6.
PS C:\Windows\system32> repadmin /replsum
Replication Summary Start Time: 2020-10-08 12:09:59

Beginning data collection for replication summary, this may take awhile:
  .....


Source DSA          largest delta    fails/total %%   error
 DC01              10m:00s    0 /   5    0
 DC02              20m:44s    0 /   5    0


Destination DSA     largest delta    fails/total %%   error
 DC01              20m:44s    0 /   5    0
 DC02              10m:00s    0 /   5    0
 
6.1.
PS C:\Windows\system32> dfsrmig /SetGlobalState 2

Current DFSR global state: 'Prepared'
New DFSR global state: 'Redirected'

Migration will proceed to 'Redirected' state. The SYSVOL share
will be changed to SYSVOL_DFSR folder,
which is replicated using DFSR.

Succeeded.

6.2
PS C:\Windows\system32> dfsrmig /GetMigrationState

The following Domain Controllers are not in sync with Global state ('Redirected'):

Domain Controller (Local Migration State) - DC Type
===================================================

DC01 ('Prepared') - Primary DC

Migration has not yet reached a consistent state on all Domain Controllers.
State information might be stale due to AD latency.

6.3
PS C:\Windows\system32> dfsrmig /GetMigrationState

All Domain Controllers have migrated successfully to Global state ('Redirected').
Migration has reached a consistent state on all Domain Controllers.
Succeeded.


7.
PS C:\Windows\system32> repadmin /replsum
Replication Summary Start Time: 2020-10-08 12:17:11

Beginning data collection for replication summary, this may take awhile:
  .....


Source DSA          largest delta    fails/total %%   error
 DC01              17m:12s    0 /   5    0
 DC02              27m:56s    0 /   5    0


Destination DSA     largest delta    fails/total %%   error
 DC01              27m:56s    0 /   5    0
 DC02              17m:12s    0 /   5    0

7.1
PS C:\Windows\system32> dfsrmig /SetGlobalState 3

Current DFSR global state: 'Redirected'
New DFSR global state: 'Eliminated'

Migration will proceed to 'Eliminated' state. It is not possible
to revert this step.

If any RODC is stuck in the 'Eliminating' state for too long
then run with option /DeleteRoNtfrsMembers.
Succeeded.

7.2
PS C:\Windows\system32> dfsrmig /GetMigrationState

The following Domain Controllers are not in sync with Global state ('Eliminated'):

Domain Controller (Local Migration State) - DC Type
===================================================

DC02 ('Redirected') - Writable DC
DC01 ('Redirected') - Primary DC

Migration has not yet reached a consistent state on all Domain Controllers.
State information might be stale due to AD latency.

7.3
PS C:\Windows\system32> dfsrmig /GetMigrationState

All Domain Controllers have migrated successfully to Global state ('Eliminated').
Migration has reached a consistent state on all Domain Controllers.
Succeeded.

7.4
PS C:\Windows\system32> dfsrmig /GetGlobalState

Current DFSR global state: 'Eliminated'
Succeeded.


References
Migrate SYSVOL replication to DFS Replication
https://docs.microsoft.com/en-us/windows-server/storage/dfs-replication/migrate-sysvol-to-dfsr

SYSVOL Migration Series: Part 1 – Introduction to the SYSVOL migration process
https://techcommunity.microsoft.com/t5/storage-at-microsoft/sysvol-migration-series-part-1-8211-introduction-to-the-sysvol/ba-p/423456

SYSVOL Migration Series: Part 2 – Dfsrmig.exe: The SYSVOL migration tool
https://techcommunity.microsoft.com/t5/storage-at-microsoft/sysvol-migration-series-part-2-8211-dfsrmig-exe-the-sysvol/ba-p/423470

SYSVOL Migration Series: Part 3 - Migrating to the 'PREPARED' state
https://techcommunity.microsoft.com/t5/storage-at-microsoft/sysvol-migration-series-part-3-migrating-to-the-prepared-state/ba-p/423503

SYSVOL Migration Series: Part 4 – Migrating to the 'REDIRECTED' state
https://techcommunity.microsoft.com/t5/storage-at-microsoft/sysvol-migration-series-part-4-8211-migrating-to-the-8216/ba-p/423514

SYSVOL Migration Series: Part 5 – Migrating to the 'ELIMINATED' state
https://techcommunity.microsoft.com/t5/storage-at-microsoft/sysvol-migration-series-part-5-8211-migrating-to-the-8216/ba-p/423516

Determining Whether a Domain Controller's SYSVOL Folder is Replicated by DFSR or FRS
https://docs.microsoft.com/en-us/windows/win32/vss/backing-up-and-restoring-an-frs-replicated-sysvol-folder?redirectedfrom=MSDN#determining-whether-a-domain-controllers-sysvol-folder-is-replicated-by-dfsr-or-frs
To determine whether DFSR or FRS is being used on a domain controller that is running Windows Server 2008, check the value of the HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\DFSR\Parameters\SysVols\Migrating Sysvols\LocalState registry subkey. If this registry subkey exists and its value is set to 3 (ELIMINATED), DFSR is being used. If the subkey does not exist, or if it has a different value, FRS is being used.

Forest and Domain Functional Levels


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