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3 exchange server 2016 1 witness DAG with DAC enabled failover question RRS feed

  • Question

  • I have a three node DAG (quorum majority) in DAC mode spanning two datacenters. 

     

    The first Datacenter (primary) has two Maibox servers (exmb1 and exmb2) in the DAG.

    The second Datacenter (drsite) has one mailbox server (exmb3) in the DAG.

     

    If primary site goes down failover to exmb3 in drsite is not automatic because the DAG has lost quorum and I cant activate the database copy in drsite manually via ecp

    How can I activate exmb3 in drsite? can you please advise me the steps? in case I activated drsite, how can I revert to my original setup which is database are mounted to primary. Thanks

    Thursday, November 21, 2019 8:54 AM

Answers

  • Hi danpaolo,
    According to your description, you have lost 2 objects in DAG. For this kind of issue, it’s suggested to active your secondary datacenter and specify a new Alternative File Share Witness Server in it, so that you can active Exchange Sever in primary datacenter.
    You can follow the steps in this article: https://docs.microsoft.com/en-us/exchange/high-availability/manage-ha/datacenter-switchovers?view=exchserver-2019#restoring-service-to-the-primary-datacenter

    Regards,

    Eric Yin


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

    Friday, November 22, 2019 9:50 AM
  • Hi danpaolo,

    Here is a brief summary of the topic you have read:
    1.Run Stop-DatabaseAvailabilityGroup -identity DAG1 -ActiveDirectorySite FIRSTSITEName on exmb12.
    If the Mailbox server is unavailable but Active Directory is operating in SiteA, run Stop-DatabaseAvailabilityGroup -identity DAG1 -ActiveDirectorySite FIRSTSITEName –ConfigurationOnly

    2.Run Stop-DatabaseAvailabilityGroup -identity DAG1 -ActiveDirectorySite FIRSTSIETName –ConfigurationOnly on exmb3 to inform which primary datacenter servers are stopped.

    3.Run Stop-service clussvc on exmb3.

    4.Run Restore-DatabaseAvailabilityGroup –identity DAG1 – ActiveDirectorySite SiteB –AlternateWitnessServer SiteB-Server-Name on exmb3.

    5.If database is activated by automatic, skip this step. If not, run Move-Activemailboxdatabase –identity “DB1” –Activateonserver SITEB –skiplagchecks–skiphealthchecks –mountdialoverride besteffort

    6.Check if any errors occur during steps above.

    7.Run Start-DatabaseAvailabilityGroup –identity DAG1–ActiveDirectorySite SiteA on exmb3 to reincorporate the DAG members in SiteA.

    8.Run Set-DatabaseAvailabilityGroup -Identity DAG1 -WitnessDirectory C:\DAG1DIR -WitnessServer exmb if you want to change DAG settings.

    9.Run Dismount -database -Identity DB1 in SiteB if you want to dismount.

    10.Run  Get-DatabaseAvailabilityGroup -status | FL to check the status.

    11.Run Move-ActiveMailboxDatabase and Mount-Database to revert to original if you want.

    I’ve found a similar thread to yours, maybe some answers will help you: https://social.technet.microsoft.com/Forums/office/en-US/e08763e3-0b07-450c-8196-d970fdd0b066/exch-2010-sp3-3-member-dag-need-manual-failover-scenario-power-down-sequence-maintain-quorum?forum=exchangesvravailabilityandisasterrecovery


    By the way, I advise you do some research about DAG by reading topics and blogs, for any errors that we can’t expect may result in failure.


    Regards,

    Eric Yin


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

    • Marked as answer by danpaolo Saturday, December 7, 2019 2:26 AM
    Monday, December 2, 2019 9:28 AM

All replies

  • Also is it possible to backup an edb file? And mount it to a different exchange server?
    Thursday, November 21, 2019 11:28 AM
  • Hi danpaolo,
    According to your description, you have lost 2 objects in DAG. For this kind of issue, it’s suggested to active your secondary datacenter and specify a new Alternative File Share Witness Server in it, so that you can active Exchange Sever in primary datacenter.
    You can follow the steps in this article: https://docs.microsoft.com/en-us/exchange/high-availability/manage-ha/datacenter-switchovers?view=exchserver-2019#restoring-service-to-the-primary-datacenter

    Regards,

    Eric Yin


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

    Friday, November 22, 2019 9:50 AM
  • Hi, I'm here to confirm with you if your issue has been resolved. If the problem is successfully solved, you can share your solution and mark them or the helpful reply as answer, this will make answer searching in the forum easier and be beneficial to other community members as well.

    Regards,

    Eric Yin


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

    Wednesday, November 27, 2019 10:36 AM
  • Hi danpaolo,
    According to your description, you have lost 2 objects in DAG. For this kind of issue, it’s suggested to active your secondary datacenter and specify a new Alternative File Share Witness Server in it, so that you can active Exchange Sever in primary datacenter.
    You can follow the steps in this article: https://docs.microsoft.com/en-us/exchange/high-availability/manage-ha/datacenter-switchovers?view=exchserver-2019#restoring-service-to-the-primary-datacenter

    Regards,

    Eric Yin


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

    Hi Eric,

    Read the link you gave to me. im having a hard time to understand and the steps provided there are very vague for me. im still searching for a specific step by step. Also, just want to confirm its possible to activate my dr site right with only 1 exchange server?

    Friday, November 29, 2019 3:12 AM
  • Hi danpaolo,

    Here is a brief summary of the topic you have read:
    1.Run Stop-DatabaseAvailabilityGroup -identity DAG1 -ActiveDirectorySite FIRSTSITEName on exmb12.
    If the Mailbox server is unavailable but Active Directory is operating in SiteA, run Stop-DatabaseAvailabilityGroup -identity DAG1 -ActiveDirectorySite FIRSTSITEName –ConfigurationOnly

    2.Run Stop-DatabaseAvailabilityGroup -identity DAG1 -ActiveDirectorySite FIRSTSIETName –ConfigurationOnly on exmb3 to inform which primary datacenter servers are stopped.

    3.Run Stop-service clussvc on exmb3.

    4.Run Restore-DatabaseAvailabilityGroup –identity DAG1 – ActiveDirectorySite SiteB –AlternateWitnessServer SiteB-Server-Name on exmb3.

    5.If database is activated by automatic, skip this step. If not, run Move-Activemailboxdatabase –identity “DB1” –Activateonserver SITEB –skiplagchecks–skiphealthchecks –mountdialoverride besteffort

    6.Check if any errors occur during steps above.

    7.Run Start-DatabaseAvailabilityGroup –identity DAG1–ActiveDirectorySite SiteA on exmb3 to reincorporate the DAG members in SiteA.

    8.Run Set-DatabaseAvailabilityGroup -Identity DAG1 -WitnessDirectory C:\DAG1DIR -WitnessServer exmb if you want to change DAG settings.

    9.Run Dismount -database -Identity DB1 in SiteB if you want to dismount.

    10.Run  Get-DatabaseAvailabilityGroup -status | FL to check the status.

    11.Run Move-ActiveMailboxDatabase and Mount-Database to revert to original if you want.

    I’ve found a similar thread to yours, maybe some answers will help you: https://social.technet.microsoft.com/Forums/office/en-US/e08763e3-0b07-450c-8196-d970fdd0b066/exch-2010-sp3-3-member-dag-need-manual-failover-scenario-power-down-sequence-maintain-quorum?forum=exchangesvravailabilityandisasterrecovery


    By the way, I advise you do some research about DAG by reading topics and blogs, for any errors that we can’t expect may result in failure.


    Regards,

    Eric Yin


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

    • Marked as answer by danpaolo Saturday, December 7, 2019 2:26 AM
    Monday, December 2, 2019 9:28 AM
  • Hi danpaolo,

    Here is a brief summary of the topic you have read:
    1.Run Stop-DatabaseAvailabilityGroup -identity DAG1 -ActiveDirectorySite FIRSTSITEName on exmb12.
    If the Mailbox server is unavailable but Active Directory is operating in SiteA, run Stop-DatabaseAvailabilityGroup -identity DAG1 -ActiveDirectorySite FIRSTSITEName –ConfigurationOnly

    2.Run Stop-DatabaseAvailabilityGroup -identity DAG1 -ActiveDirectorySite FIRSTSIETName –ConfigurationOnly on exmb3 to inform which primary datacenter servers are stopped.

    3.Run Stop-service clussvc on exmb3.

    4.Run Restore-DatabaseAvailabilityGroup –identity DAG1 – ActiveDirectorySite SiteB –AlternateWitnessServer SiteB-Server-Name on exmb3.

    5.If database is activated by automatic, skip this step. If not, run Move-Activemailboxdatabase –identity “DB1” –Activateonserver SITEB –skiplagchecks–skiphealthchecks –mountdialoverride besteffort

    6.Check if any errors occur during steps above.

    7.Run Start-DatabaseAvailabilityGroup –identity DAG1–ActiveDirectorySite SiteA on exmb3 to reincorporate the DAG members in SiteA.

    8.Run Set-DatabaseAvailabilityGroup -Identity DAG1 -WitnessDirectory C:\DAG1DIR -WitnessServer exmb if you want to change DAG settings.

    9.Run Dismount -database -Identity DB1 in SiteB if you want to dismount.

    10.Run  Get-DatabaseAvailabilityGroup -status | FL to check the status.

    11.Run Move-ActiveMailboxDatabase and Mount-Database to revert to original if you want.

    I’ve found a similar thread to yours, maybe some answers will help you: https://social.technet.microsoft.com/Forums/office/en-US/e08763e3-0b07-450c-8196-d970fdd0b066/exch-2010-sp3-3-member-dag-need-manual-failover-scenario-power-down-sequence-maintain-quorum?forum=exchangesvravailabilityandisasterrecovery


    By the way, I advise you do some research about DAG by reading topics and blogs, for any errors that we can’t expect may result in failure.


    Regards,

    Eric Yin


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

    Hi Eric,

    I just have few questions please.

    1.Run Stop-DatabaseAvailabilityGroup -identity DAG1 -ActiveDirectorySite FIRSTSITEName on exmb12.
    If the Mailbox server is unavailable but Active Directory is operating in SiteA, run Stop-DatabaseAvailabilityGroup -identity DAG1 -ActiveDirectorySite FIRSTSITEName –ConfigurationOnly

    -In example we have a disaster on our primary site building and both exchange server has been shutdown and AD is shutdown also, should I skip this step and proceed to step 2?

    "7.Run Start-DatabaseAvailabilityGroup –identity DAG1–ActiveDirectorySite SiteA on exmb3 to reincorporate the DAG members in SiteA."

    - when should I run this step 7? is this part of failback procedure?

    8.Run Set-DatabaseAvailabilityGroup -Identity DAG1 -WitnessDirectory C:\DAG1DIR -WitnessServer exmb if you want to change DAG settings.

    -This one is confusing I compare it to the link you have provided and it says run "Set-DatabaseAvailabilityGroup -Identity LON-DAG" to Reactivate DAG if same original FSW is to be used at production site."

    Should I run this on exmb3 or on the primary servers?(exmb1,exmb2)?

    Thank you so much.

    Regards,

    Pao

    Monday, December 2, 2019 11:48 AM
  • Hi danpaolo,
    1. “This step may not be possible depending on the failure. This step should be taken if the state of the datacenter permits it.” If SiteA is shutdown, you should skip it and go to step2.
    2.” When the environment (such as primary datacenter, Exchange dependencies, and wide area network (WAN) connectivity) is ready, the first step is to put the Mailbox servers in the restored primary datacenter into a started state and incorporate them into the DAG.” Since step1 has evicted exmb12 from  the DAG, this step is to bring them back.
    3. It depends if you have re-added SiteA. You can run set-databaseavailabilitygroup -identity without other parameters if you don’t want to change the witness server. This step is to “make sure that the proper quorum model is being used by the DAG”.

    Please be free to mark your reply or other useful reply as answer to highlight it, this will make answer searching in the forum easier and be beneficial to other community members as well.

    Regards,

    Eric Yin


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

    Tuesday, December 3, 2019 10:17 AM
  • Hi, I'm here to confirm with you if your issue has been resolved. If the problem is successfully solved, you can share your solution and mark them or the helpful reply as answer, this will make answer searching in the forum easier and be beneficial to other community members as well.

    Regards,

    Eric Yin


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

    Friday, December 6, 2019 10:10 AM
  • I’m pleased to know that the information is helpful to you.
     
    Here I will provide a brief summary of this post so that other forum members could easily find useful information here:
    [Exchange Server > Exchange Server 2016 -3 exchange server 2016 1 witness DAG with DAC enabled failover question  — Summary]
     
     
    Issue Symptom:
    Exmb1 and Exmb2 do down, how can exmb3 active the database copy

    (Possible) Cause:
    Unexpected events
        
     
    Solution:
    1. stop the DAG and service
    2. active the standby datacenter
    3. move the database 
    4. restart the DAG



     
    Reference Links:https://docs.microsoft.com/en-us/exchange/high-availability/manage-ha/datacenter-switchovers?view=exchserver-2019#restoring-service-to-the-primary-datacenter
     
    Monday, December 9, 2019 1:43 AM