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exchange dag automatic failover RRS feed

  • Question

  • DEARS,

    i have 2 2016 exchange servers configured in DAG mode, i'm facing the following:

    all my databases are mounted on exchange A, and exchange B hold the passive copies, when i rebooted my exchange A server, databases failed over to exchange B. Now exchange B is holding the active copies, i realized when Exchange A is up again, after approximately 1 hour, databases are active again on Exchange A without my intervention.

    Even when i manually activate it the databases from A to B, after a while they automatically get activated again on A without my intervention.

    Is this behavior normal?

    Please advise

    thank you

    Wednesday, November 7, 2018 2:42 PM

Answers

  • Hi eg1559,

    It is a normal behavior, because the active site has more vote than the passive site, so databases will be mounted on it.

    If you don't want active copy switch back to active site when this site restarts, you should configure DAC for your DAG.

    Set-DatabaseAvailabilityGroup -Identity DAG2 -DatacenterActivationMode DagOnly

    Regards,

    Kyle Xu


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    • Marked as answer by eg1559 Friday, November 9, 2018 6:22 AM
    Thursday, November 8, 2018 8:47 AM
    Moderator

All replies

  • are you CU2?

    https://practical365.com/exchange-server/new-dag-activation-preference-behavior-exchange-2016-cu2-good-news/

    Wednesday, November 7, 2018 2:53 PM
  • no deat, cu7
    Thursday, November 8, 2018 7:11 AM
  • then is by design, new feature in CU2
    Thursday, November 8, 2018 8:37 AM
  • Hi eg1559,

    It is a normal behavior, because the active site has more vote than the passive site, so databases will be mounted on it.

    If you don't want active copy switch back to active site when this site restarts, you should configure DAC for your DAG.

    Set-DatabaseAvailabilityGroup -Identity DAG2 -DatacenterActivationMode DagOnly

    Regards,

    Kyle Xu


    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.

    Click here to learn more. Visit the dedicated forum to share, explore and talk to experts about Microsoft Teams.

    • Marked as answer by eg1559 Friday, November 9, 2018 6:22 AM
    Thursday, November 8, 2018 8:47 AM
    Moderator
  • Is this true?  Just because the Active Site has more votes it will automatically keep failing back to the active site?  The votes only count during an outage right?  Wherever the FSW is and the majority node set wins and hence becomes active

    -C-

    Thursday, August 15, 2019 8:46 PM