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Quantum2021-0808 avatar image
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Quantum2021-0808 asked Quantum2021-0808 answered

One of the 2 DFS-replication group members' data drive crashed. How to restore data in this case?

DFS-R setup:
Using DFS-Replication and not using DFS-Namespace
File server A (2012) and server B (2019) in the replication group and are in the same physical location. They are also DCs, just an FYI.
File server A is the primary member
Topology is Full Mesh
Multipurpose Replication group
The data size is about 1 TB.


We have a number of share folders on server A and B.
Users have their drives mapped to server B as its a newer server and Server A is there as just in case.
The shares are identical on both servers A and B and DFS-R is used to keep the data in sync on both servers and DFS-R is in "Full Mesh" mode and setup as "multipurpose replication group".

Today, server A's data partition where all the shares are, crashed so although the server A's OS is fine and running, the shares are not accessible on it.
Users are not impacted as their share drives are mapped to Server B.

Server A's data partition will be fixed in a couple days.
How would I go about restoring server A's data and have the DFS-R sync normally after fixing the data partition?

Do I simply re-create the folders and share them on Server A and let DFS-R take care of the data restore automatically from Server B or do I restore Server A's data using backup and let DFS-R sync the changed files since the crash? I would prefer to have DFS-R take care of the data restore automatically.
And since server A was the primary member when DFS-R was first setup and thus authoritative, is there anything I need to do differently in order to accomplish that? I need the data on Server B to be used.
It's in Full mesh so I'm not sure if server A being the primary member matters.
And since server A's data partition is down, should I manually stop the DFS service on both servers for now to avoid any new issues or remove server A from the replication group or does it not matter?

Thanks

windows-server-2019windows-server-2012windows-server-storage
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DaisyZhou-MSFT avatar image
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DaisyZhou-MSFT answered Quantum2021-0808 edited

Hello @Quantum2021-0808,

Thank you for posting here.

Here is the suggestion.

If server A's data partition is fixed in a couple days. We can copy all the data from server B to server A using robocopy or xcopy at your convenience or at downtime.

Then remove the member of server A and recreate member of server A in DFS managemment.

So all the new data on server A will be replicated to server B from server A.

So all the new data on server B will be replicated to server A from server B.


References:

robocopy
https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/robocopy

xcopy
https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/xcopy

DFS Replication Initial Sync in Windows Server 2012 R2: Attack of the Clones
https://techcommunity.microsoft.com/t5/storage-at-microsoft/dfs-replication-initial-sync-in-windows-server-2012-r2-attack-of/ba-p/424877

DFS Replication: Copying Files to Preseed or Stage Initial Synchronization
https://docs.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2012-r2-and-2012/dn495052(v=ws.11)

Hope the information above is helpful.

Should you have any question or concern, please feel free to let us know.

Tip: It is best to simulate the current scenario in the test environment, first use this method in the test environment, if everything is OK, use this method in the production environment if possible and needed.


Best Regards,
Daisy Zhou

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Thanks.
I used robocopy with preseed when I setup the DFS-R the first time so I'll just do the same.

When "Then remove the member of server A and recreate member of server A in DFS managemment.", is there any steps involved in doing this such as removing the DFSR private folders on server B or just do the robocopy using preseed from server B to A then add server A to the DFS-R group?
Server A's name will be retained FYI.

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DaisyZhou-MSFT avatar image
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DaisyZhou-MSFT answered

Hello @Quantum2021-0808,

I am sorry for the late reply.

Thank you for your reply and accept my reply as answer.

1.Opne DFS amangement.

2.Delete the member we want.
66235-dfs0.png

3.Add the member we want and follow the wizard.
66271-dfs01.png

4.After that, we update the DFS information by running DFSRDIAG POLLAD on DFS server.
66291-dfs1.png

5.Update the AD replication by running repadmin /syncall /AdeP on DC.
66272-dfs2.png

6.Click Replicate Now on DFS member server connection.
66293-dfs5.png


Best Regards,
Daisy Zhou



dfs0.png (22.7 KiB)
dfs01.png (40.9 KiB)
dfs1.png (2.6 KiB)
dfs2.png (345.1 KiB)
dfs5.png (49.6 KiB)
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Quantum2021-0808 avatar image
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Quantum2021-0808 answered

Thanks for the detailed information!

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Quantum2021-0808 avatar image
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Quantum2021-0808 answered

There's no need to remove all the DFSR private folders on server B?
When server A is added back, it'll be using the exact same name before the crash.

Thanks

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