Migration of SYSVOL replications from FRS to DFSR

Note: If we install a new domain with Windows Server 2008, DFSR will be used immediately.

SYSVOL Folder

The SYSVOL (System Volume) folder contains public files that clients on the network can access. These include Group Policy (group policies, templates can also be stored here) and scripts and the Default User profile (previously the NETLOGON folder). Unlike the Active Directory database, where changes are replicated (using RPC or SMTP), in Sysvol (using FRS), entire files are replicated.

Using DFSR brings greater performance, replication scheduling, the ability to use the DFS Management MMC console, and more. We discussed the DFS technology in more detail in the article Description of DFS and migration to Windows Server 2008 mode. Generally, the transition to DFSR is strongly recommended.

The Sysvol folder is located on each DC by default in the path C:\Windows\SYSVOL\sysvol. Here there is a directory with the domain name, which is actually a Junction Point to the C:\Windows\SYSVOL\domain folder. There are also the Policies (where the GPOs and GPTs are) and Scripts (which is shared for historical reasons as NETLOGON) subfolders.

Migration to DFSR

To be able to transition from FRS to DFSR, we must have the domain at the Windows Server 2008 functional level. On all DCs, we must install the DFS Replication role (Roles - File Services - Distributed File System - DFS Replication). Then, we can use the dfsrmig.exe command on any DC, which is part of Windows Server 2008 and Windows Server 2008 R2. On Windows Server 2008, it is recommended to have SP2 installed, which improves replication (I prefer the R2 version directly).

Before we start switching the replications, I definitely recommend checking that our current replications are running without errors.

Migration is quite simple, we can perform the entire process using a single command, and it takes place in several steps. The idea is that a second folder SYSVOL_DFSR is created next to the SYSVOL folder, which is replicated using DFSR. The individual migration states are:

• 0 - Start - only FRS is used
• 1 - Prepared - a copy of the SYSVOL folder is created, and it starts being replicated using DFSR, but clients still access the original one
• 2 - Redirected - the share is redirected to the new SYSVOL_DFSR folder, so clients connect to the newly replicated folder, but both replications are still running
• 3 - Eliminated - the original folder, all records are removed, and the FRS service is turned off, from this state it is no longer possible to go back

C:\>dfsrmig /GetGlobalState

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

C:\>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.

C:\>dfsrmig /GetGlobalState

Current DFSR global state: 'Prepared'
Succeeded.

Further, we gradually proceed through state 2, where we can still return to state 0, until the final state 3. In this state, we get the following information, which is the same as when we installed a 2008 domain from scratch.

C:\>dfsrmig /GetGlobalState

Current DFSR global state: 'Eliminated'
Succeeded.

For a more detailed description of the entire issue, I recommend the English articles SYSVOL Migration Series: Part 1 - Introduction to the SYSVOL migration process or Introduction to Administering DFS-Replicated SYSVOL.