FileShareWitness disappeared and all databases dismounted

Innocent Heartvoice 296 Reputation points
2024-11-14T11:49:44.49+00:00

In Exchange 2013, I have a DAG with three mailbox servers: two in the primary site and one in a DR site. The issue I'm facing is that, occasionally, due to a connectivity issue, the file share witness or quorum disk becomes unavailable, and as a result, all databases show as dismounted. After 3 to 4 hours, the disk becomes available again, though the cause of the issue is unknown.

Could you please suggest the root cause of this issue and how to resolve it?

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  1. Andy David - MVP 150.2K Reputation points MVP
    2024-11-14T12:41:21.19+00:00

    With three mailbox servers, the File Share witness is not used. ITs for DAGs with an even number of mailbox servers.

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  2. Jake Zhang-MSFT 7,235 Reputation points Microsoft Vendor
    2024-11-15T05:45:32.6466667+00:00

    Hi @Innocent Heartvoice ,

    Welcome to the Microsoft Q&A platform!

    Based on your description, you are experiencing issues with the File Share Witness (FSW) in a Database Availability Group (DAG). When the FSW or quorum disk is unavailable, the DAG loses quorum, causing all databases to unmount.

     

    Here are some potential causes:

    1. Intermittent network issues between the DAG members and the FSW can cause the FSW to be unavailable.
    2. Issues with the server hosting the FSW (such as hardware failure or software issues) can cause the FSW to be unavailable.
    3. Incorrect configuration of the FSW or quorum settings can cause availability issues.

     

    You can try the following methods to resolve the issue:

    1. Ensure that the network connection between all DAG members and the FSW server is stable and reliable. Use network monitoring tools to identify and resolve any intermittent connection issues.
    2. Check the health and performance of the server hosting the FSW. Ensure that the server is not experiencing hardware or software issues that may affect its availability.
    3. If the FSW cluster resource is offline, you can bring it back online using PowerShell:
    Get-ClusterResource -Name "File Share Witness" | Start-ClusterResource
    

    This command checks the status of the FSW cluster resource and starts it if it is offline.

    1. If restarting the FSW cluster resource does not resolve the issue, you may need to recreate the FSW:
    Set-DatabaseAvailabilityGroup -Identity DAGName -WitnessServer NewWitnessServer -WitnessDirectory NewWitnessDirectory
    

    Replace DAGName, NewWitnessServer, and NewWitnessDirectory with your actual DAG name, new witness server, and directory.


    Please feel free to contact me for any updates. And if this helps, don't forget to mark it as an answer.

    Best,

    Jake Zhang


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