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Mounting Database on Secondary DAG member without Primary Member or Witness RRS feed

  • Question

  • Hi -I built a test environment that has my AD and member servers up and running.

    I brought an Exchange DAG member VM into the test environment without the other DAG member or witness server. The DAG member in the test environment is normally passive and the other DAG member (not existing in the test environment) is normally active.

    I have tried:

    1)Activating the Database on the VM (fails)

    2) Server Switchover in the console (fails)

    2) creating a new witness server with the Set-DatabaseAvailabilityGroup command (will not occur without the normally active )

    3) Deleting the normally active server from the DAG (does not work)

    4) Deleting the DAG (does not work without the other member)

    5)Force mounting the database while ignoring errors - Fails

    Is there a simple way I can get this DAG member server to work without the other DAG member or witness?

    Thanks!


    • Edited by strongbad2 Thursday, April 25, 2019 6:11 PM
    Thursday, April 25, 2019 5:45 PM

Answers

  • Hi Andy.

    Its a test environment. I have my Domain Controllers and other servers running in it. I am simulating a situation where both the active server and witness server are offline and unavailable and all I have is the passive server.

    I am trying to verify that a client machine in the test environment can still open outlook and retrieve emails from this passive VM in this test environment. All other applications/file/print/AD have been verified and this is the last piece I want to verify.

    If it helps, the available DAG member reports a database status of "Passive Disconnected and resynchronizing" and the missing, (normally active) DAG member reports as "Passive ServiceDown".

    Thanks

    Ok, in this scenario, assuming all the servers were down hard and you needed to boot and mount the databases on a single server, you would have to force quorum on that server

    https://docs.microsoft.com/en-us/exchange/high-availability/manage-ha/datacenter-switchovers?view=exchserver-2019

    Follow the guidance for DAC mode if enabled, if not follow the force quorum instructions under the section:

    When the DAG isn't in DAC mode, the specific actions to terminate any surviving DAG members in the primary datacenter are as follows:

    However!

    Note that depending on how the node and FSW went down, the last server may still be up and running assuming you are using at least 2012 R2 then dynamic quorum may save you and keep that last server running

    https://social.technet.microsoft.com/wiki/contents/articles/32325.exchange-2013-how-does-dynamic-quorum-work-for-a-two-node-dag.aspx

    • Marked as answer by strongbad2 Friday, April 26, 2019 12:21 PM
    Thursday, April 25, 2019 8:15 PM
    Moderator

All replies

  • Hi -I built a test environment that has my AD and member servers up and running.

    I brought my Exchange secondary DAG member into the test environment without the primary DAG member or witness server.

    I have tried:

    1)Activating the Database on the secondary (fails)

    2) Server Switchover in the console (fails)

    2) creating a new witness server with the Set-DatabaseAvailabilityGroup command (will not occur without primary available)

    3) Deleting the primary server from the DAG (does not work)

    4) Deleting the DAG (does not work without the primary)

    5)Force mounting the database while ignoring errors - Fails

    Is there a simple way I can get this secondary server to work without the primary or witness?

    Thanks!

    Not sure I really understand. There is no such thing as a primary or secondary server in a DAG, but regardless, what happened to the other server in the cluster?
    Thursday, April 25, 2019 6:03 PM
    Moderator
  • Sorry, I only have a two node DAG so I have fallen into the habit of calling them primary and secondary.

    It is just a test environment and I have only loaded into it the VM that would normally not be the active database.

    So in my case, I am editing the original question to call the secondary the "passive" DAG member and the primary the "normally active".

    Thursday, April 25, 2019 6:09 PM
  • Sorry, I only have a two node DAG so I have fallen into the habit of calling them primary and secondary.

    It is just a test environment and I have only loaded into it the VM that would normally not be the active database.

    So in my case, I am editing the original question to call the secondary the "passive" DAG member and the primary the "normally active".

    Can you describe what you have setup and what you are trying to do? Im still not clear. Is the active server up? If not, what happened to it?
    Thursday, April 25, 2019 6:42 PM
    Moderator
  • Hi Andy.

    Its a test environment. I have my Domain Controllers and other servers running in it. I am simulating a situation where both the active server and witness server are offline and unavailable and all I have is the passive server.

    I am trying to verify that a client machine in the test environment can still open outlook and retrieve emails from this passive VM in this test environment. All other applications/file/print/AD have been verified and this is the last piece I want to verify.

    If it helps, the available DAG member reports a database status of "Passive Disconnected and resynchronizing" and the missing, (normally active) DAG member reports as "Passive ServiceDown".

    Thanks

    Thursday, April 25, 2019 6:58 PM
  • Hi Andy.

    Its a test environment. I have my Domain Controllers and other servers running in it. I am simulating a situation where both the active server and witness server are offline and unavailable and all I have is the passive server.

    I am trying to verify that a client machine in the test environment can still open outlook and retrieve emails from this passive VM in this test environment. All other applications/file/print/AD have been verified and this is the last piece I want to verify.

    If it helps, the available DAG member reports a database status of "Passive Disconnected and resynchronizing" and the missing, (normally active) DAG member reports as "Passive ServiceDown".

    Thanks

    Ok, in this scenario, assuming all the servers were down hard and you needed to boot and mount the databases on a single server, you would have to force quorum on that server

    https://docs.microsoft.com/en-us/exchange/high-availability/manage-ha/datacenter-switchovers?view=exchserver-2019

    Follow the guidance for DAC mode if enabled, if not follow the force quorum instructions under the section:

    When the DAG isn't in DAC mode, the specific actions to terminate any surviving DAG members in the primary datacenter are as follows:

    However!

    Note that depending on how the node and FSW went down, the last server may still be up and running assuming you are using at least 2012 R2 then dynamic quorum may save you and keep that last server running

    https://social.technet.microsoft.com/wiki/contents/articles/32325.exchange-2013-how-does-dynamic-quorum-work-for-a-two-node-dag.aspx

    • Marked as answer by strongbad2 Friday, April 26, 2019 12:21 PM
    Thursday, April 25, 2019 8:15 PM
    Moderator
  • Thanks very much! I will attempt to force quorum in my test environment soon and advise for future readers...
    Friday, April 26, 2019 12:22 PM