Problem with DFS

Question

Problem with DFS

Михаил Андросов 456

Hi!

I am using embedded DFS replication based on Windows Server 2012 R2. There are a total of 14 WEB2 - WEB14 servers in the group. WEB2 and WEB3 are server versions that are copied for familiarization with other server versions. Recently, I was surprised that the WEB4 server asked me to pay attention to representative files. Other servers replicate normally, but this one doesn't. We tried restarting the servers. I can't find any errors. And the diagnostic reports run without errors.

Before restarting on the web02 server, an error was detected in the event log:

DFSR/5008

The DFS Replication service failed to communicate with partner BP-DN-WEB03 for replication group bp-dn-web. This error can occur if the host is unreachable, or if the DFS Replication service is not running on the server.

Partner DNS Address: web03

Optional data if available:

Partner WINS Address: web03

Partner IP Address: 192.168.70.143

The service will retry the connection periodically.

Additional Information:

Error: 1722 (The RPC server is unavailable.)

Connection ID: 3EE81815-7FBD-402B-A2AD-844E733600D5

Replication Group ID: B52F9D2F-8211-46F5-87D2-A779FC238971

After reboot, the logs do not contain errors. I've done this kind of work. Took the web04 server out of replication. I cleaned the replicated folder. Added a replication server. The server rebooted because a web02 communication error was registered Enough time has passed. But the folder remains empty. Replication is not performed. There are no errors in the logs.

Can someone explain to me why the problem is occurring and how to resolve it?

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Answer 1

Hi Михаил Андросов,

Based on your symptoms, it’s very likely that WEB4 is stuck due to DFS Replication database divergence, especially after you removed and re-added it to the replication group. Even when the logs are clean, DFSR will not replicate if the local database still contains stale state information or if it believes it is already “in sync.” The earlier Event 5008 / RPC 1722 between WEB02 and WEB03 also suggests there was a temporary communication failure that may have caused USN journal gaps or database inconsistencies in downstream partners like WEB4.

To fix this, I recommend performing an authoritative / non-authoritative DFSR rebuild on WEB4. This involves stopping the DFSR service, renaming the hidden System Volume Information\DFSR database folder, and letting DFSR fully rebuild the database from its partners. You should also confirm that the replicated folder permissions and staging/quota sizes are correct, and verify that WEB4 can resolve and RPC-connect to the upstream partner using dfsrdiag pollad, dfsrdiag backlog, and dfsrdiag replicationstate. If WEB4 still shows an empty folder after the rebuild, you may need to perform an authoritative sync from WEB02 (healthiest source) to force WEB4 to fully re-seed.

Feel free to share the results of dfsrdiag backlog /partner:WEB02 and I can help interpret the replication state.

If these steps help point you in the right direction, please hit “Accept Answer” so I know it resolved your concern 😊.

Jason.

Answer 2

It seems you are experiencing issues with DFS replication involving the WEB4 server, which is not replicating correctly with the other servers in your group. The error you mentioned (DFSR/5008) indicates a communication failure between the DFS Replication service on WEB2 and its partner WEB03. The error code 1722 (The RPC server is unavailable) suggests that there may be network connectivity issues, or the DFS Replication service might not be running on the partner server.

Here are some steps you can take to troubleshoot and potentially resolve the issue:

Check Network Connectivity: Ensure that WEB2 can reach WEB03 over the network. You can use tools like ping or tracert to verify connectivity.
Verify DFS Replication Service: Make sure that the DFS Replication service is running on both WEB2 and WEB03. You can check this in the Services management console or by using the command line.
Review Event Logs: Although you mentioned that there are no errors in the logs after the reboot, it’s worth checking both the Application and System event logs for any warnings or errors that might provide additional context.
Check Firewall Settings: Ensure that the firewall settings on both servers allow for the necessary RPC communication. The default ports for DFS Replication should be open.

Evaluate DFS Replication State: Use the command to check the state of DFS Replication on all domain controllers. This can help identify if there are any other underlying issues with the replication setup.

   For /f %i IN ('dsquery server -o rdn') do @echo %i && @wmic /node:"%i" /namespace:\\root\microsoftdfs path dfsrreplicatedfolderinfo WHERE replicatedfoldername='SYSVOL share' get replicationgroupname,replicatedfoldername,state

Check for Content Freshness: Ensure that content freshness is not causing the replication to be paused. You can check the MaxOfflineTimeInDays setting to see if it is set appropriately.
```
   wmic.exe /node:%computername% /namespace:\\root\microsoftdfs path DfsrMachineConfig get MaxOfflineTimeInDays
```
Reinitialize Replication: If the above steps do not resolve the issue, you might consider reinitializing the DFS Replication for the affected folder. However, be cautious as this can lead to data loss if not done correctly.

By following these steps, you should be able to identify the cause of the replication issue and take appropriate actions to resolve it. If the problem persists, consider reaching out to Microsoft support for further assistance.

References:

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Problem with DFS

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