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how to configure DAG auto fail over and fall back RRS feed

  • Question

  • Exchange 2016 on-pre

    1. how can I enable it or if needed how to disable it for manual fail over/fall back?

    2. during maintenance like applying Windows server updates or Exchange SP/CU.  If set to auto fail over/fall back should I disable it? Normally I would think applying updates on the passive nodes (DR site) first.  It shouldn't trigger fail over.  When applying on the primary site I'll do one at a time, total 4 servers plus a witness.  It shouldn't trigger a fail over.

    3. what's a recommended configure, auto fail over/fall back or manual?

    Thanks.

    Monday, May 6, 2019 5:28 PM

All replies

  • Exchange 2016 on-pre

    1. how can I enable it or if needed how to disable it for manual fail over/fall back?

    2. during maintenance like applying Windows server updates or Exchange SP/CU.  If set to auto fail over/fall back should I disable it? Normally I would think applying updates on the passive nodes (DR site) first.  It shouldn't trigger fail over.  When applying on the primary site I'll do one at a time, total 4 servers plus a witness.  It shouldn't trigger a fail over.

    3. what's a recommended configure, auto fail over/fall back or manual?

    Thanks.

    I'm not really sure what you are asking, but when updating DAG members, put them in maintenance mode before applying the updates.

    https://docs.microsoft.com/en-us/exchange/high-availability/manage-ha/manage-dags?view=exchserver-2019#performing-maintenance-on-dag-members

    https://docs.microsoft.com/en-us/exchange/plan-and-deploy/install-cumulative-updates?view=exchserver-2019

    Monday, May 6, 2019 9:56 PM
    Moderator
  • Hi,

    Switchovers and failovers are the two forms of outages in Microsoft Exchange Server:

    A failover is an automatic activation process that can occur at the database, server, or datacenter level. Failovers occur in response to a failure that affects an individual database, an entire server or an entire site.

    A switchover is a scheduled outage of a database or server that's explicitly initiated by a cmdlet or by the managed availability system in Exchange Server. Switchovers are typically done to prepare for performing a maintenance operation. 

    You don't have to enable failover manually. If you want to perform a maintenance operation, you can perform a server switchover by EAC or using commands.

    Check the steps of performing maintenance (in the first link provided by Andy), we can see that StartDagServerMaintenance.ps1 will help us move all active databases, and prevent any database copies from being activated on the server. We don't have to worry too much about the failover or switchover.

    You can check this article to learn more about switchovers and failovers: Switchovers and failovers

    Regards,

    Lydia Zhou


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

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    Tuesday, May 7, 2019 6:46 AM
    Moderator
  • Hi,

    Is there any update on this thread?

    Do you get help from above information?

    If the issue has been resolved, please mark the helpful replies as answers, this will make answer searching in the forum easier and be beneficial to other community members as well. Thanks for your understanding.

    Regards,

    Lydia Zhou


    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.

    Friday, May 10, 2019 2:05 AM
    Moderator
  • Thanks for the answers.  Actually I was asking for data center failover.  I recall in Exchange 2010 when configured a DAG there was an option whether you want to set auto cross site failover or manual.  We set manual because we had some network issue at the primary data center.  The core switch would freeze for 5-10 seconds sometimes.  Failover to the DR site would take longer.

    Now, I'm working for a company with Exchange 2016 on premise.  One day a network engineer was working on a core switch at the primary date center.  Somehow, the switch got rebooted which triggered Exchange auto failover to the DR site.  Before Exchange finished its failover the switch came back online.  But the failover continued.  About 10-15 minutes later Exchange auto fall back.  

    That's why I'm trying to find out if it's possible to set Exchange 2016 DAG to manually control its cross site failover.

    Thanks,

     
    Friday, May 17, 2019 5:43 AM
  • Thanks for the answers.  Actually I was asking for data center failover.  I recall in Exchange 2010 when configured a DAG there was an option whether you want to set auto cross site failover or manual.  We set manual because we had some network issue at the primary data center.  The core switch would freeze for 5-10 seconds sometimes.  Failover to the DR site would take longer.

    Now, I'm working for a company with Exchange 2016 on premise.  One day a network engineer was working on a core switch at the primary date center.  Somehow, the switch got rebooted which triggered Exchange auto failover to the DR site.  Before Exchange finished its failover the switch came back online.  But the failover continued.  About 10-15 minutes later Exchange auto fall back.  

    That's why I'm trying to find out if it's possible to set Exchange 2016 DAG to manually control its cross site failover.

    Thanks,

     

    Enable DAC mode:

    https://docs.microsoft.com/en-us/exchange/high-availability/database-availability-groups/dac-mode?view=exchserver-2019

    Block the server from auto activation

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

    Saturday, May 18, 2019 11:02 AM
    Moderator
  • Hi,

    Did you check the articles Andy provided?

    If you need further help, please feel free to reply this post directly so we will be notified to follow it up. If you have solved your problem, don't forget to mark it as answer, this will be easy for other community members to find the useful one. Thanks for your understanding.

    Regards,

    Lydia Zhou


    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.

    Thursday, May 23, 2019 1:36 AM
    Moderator