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Mailbox server cannot be removed from DAG
You like to remove a mailbox server from DAG (Database Availability Group). However, when performing the removal task, you get the error: Mailbox server cannot be removed from the Database Availability Group because mailbox database has multiple copies. Use Remove-MailboxDatabaseCopy either to remove the copy from this server or to remove the copies from other servers in the database availability group. Why is this happening, and what is the solution to remove the mailbox server from DAG?
Table of contents
Mailbox server cannot be removed from Database Availability Group
Sign in to Exchange admin center. Click on servers > database availability groups. Click in the list on the DAG and follow with the Manage DAG membership icon in the toolbar.
In our example, we have the following DAG configuration:
- Name: DAG01-2016
- Witness server: FS01-2016
- Member servers: EX01-2016, EX02-2016
Click the member server in the list and click on the delete icon. In our example, it’s member server EX01-2016. Click on Save.
You get the below error. It means that there are mailbox databases with database copies on the member server.
ERROR
Mailbox server ‘EX01-2016’ cannot be removed from the database availability group because mailbox database ‘DB01’ has multiple copies. Use Remove-MailboxDatabaseCopy either to remove the copy from this server or to remove the copies from other servers in the database availability group.
Solution to mailbox server cannot be removed from DAG
The solution to the error mailbox server cannot be removed from the database availability group because mailbox database has multiple copies is to remove the mailbox database copies from that Exchange Server. After that, you can remove the mailbox server from DAG.
Follow the below steps.
Step 1. Get mailbox database copies
Run Exchange Management Shell as administrator. Run the Get-MailboxDatabaseCopyStatus cmdlet to list the database copies.
[PS] C:\>Get-MailboxDatabaseCopyStatus * | sort Name | ft -AutoSize
Name Status CopyQueueLength ReplayQueueLength LastInspectedLogTime ContentIndexState
---- ------ --------------- ----------------- -------------------- -----------------
DB01\EX01-2016 Mounted 0 0 Healthy
DB01\EX02-2016 Healthy 0 0 9/6/2021 8:43:53 PM Healthy
DB02\EX01-2016 Healthy 0 0 9/6/2021 8:07:23 PM Healthy
DB02\EX02-2016 Mounted 0 0 Healthy
DB03\EX01-2016 Mounted 0 0 Healthy
DB03\EX02-2016 Healthy 0 0 9/6/2021 8:43:32 PM Healthy
DB04\EX01-2016 Healthy 0 0 9/6/2021 8:09:48 PM Healthy
DB04\EX02-2016 Mounted 0 0 Healthy
There are mailbox database copies mounted on the Exchange Server EX01-2016. You will get an error if you like to remove the database copy.
Step 2. Move mailbox database copies
Move all the database copies to another Exchange Server. Read more on how to perform a server switchover with PowerShell.
[PS] C:\>Move-ActiveMailboxDatabase -Server "EX01-2016" -ActivateOnServer "EX02-2016" -SkipMoveSuppressionChecks -Confirm:$false
Step 3. Remove mailbox database copy
Run the Remove-MailboxDatabaseCopy cmdlet. Specify the database and Exchange Server.
[PS] C:\>Remove-MailboxDatabaseCopy -Identity "DB01\EX01-2016" -Confirm:$false
WARNING: The copy of mailbox database "DB01" on server "EX01-2016" has been removed. If necessary, manually delete the database copy's files located at "F:\DB01" and "E:\DB01\DB01.edb" on that server.
Step 4. Remove mailbox database copies from particular Exchange Server
If you want to speed up the database copy removal, select the DAG member server and remove all the mailbox database copies.
[PS] C:\>Get-MailboxDatabaseCopyStatus -Server "EX01-2016" | Remove-MailboxDatabaseCopy -Confirm:$false
WARNING: The copy of mailbox database "DB02" on server "EX01-2016" has been removed. If necessary, manually delete the database copy's files located at "H:\DB02" and "G:\DB02\DB02.edb" on that server.
WARNING: The copy of mailbox database "DB03" on server "EX01-2016" has been removed. If necessary, manually delete the database copy's files located at "J:\DB01" and "I:\DB03\DB03.edb" on that server.
WARNING: The copy of mailbox database "DB04" on server "EX01-2016" has been removed. If necessary, manually delete the database copy's files located at "L:\DB04" and "K:\DB04\DB04.edb" on that server.
Step 5. Verify that there are no mailbox database copies mounted
Run the Get-MailboxDatabaseCopyStatus cmdlet and verify that you don’t see the Exchange Server in the list.
[PS] C:\>Get-MailboxDatabaseCopyStatus * | sort Name | ft -AutoSize
Name Status CopyQueueLength ReplayQueueLength LastInspectedLogTime ContentIndexState
---- ------ --------------- ----------------- -------------------- -----------------
DB01\EX02-2016 Mounted 0 0 Healthy
DB02\EX02-2016 Mounted 0 0 Healthy
DB03\EX02-2016 Mounted 0 0 Healthy
DB04\EX02-2016 Mounted 0 0 Healthy
Step 6. Remove mailbox server from DAG
Remove the mailbox member server from DAG. In our example, it’s the Exchange Server EX01-2016 and DAG DAG01-2016.
[PS] C:\>Remove-DatabaseAvailabilityGroupServer -Identity "DAG01-2016" -MailboxServer "EX01-2016" -Confirm:$false
If the Exchange mailbox server is lost and can’t be contacted, you need to use the ConfigurationOnly switch. An example is when the Exchange mailbox server fails to start.
[PS] C:\>Remove-DatabaseAvailabilityGroupServer -Identity "DAG01-2016" -MailboxServer "EX01-2016" -ConfigurationOnly -Confirm:$false
That’s it!
Read more: Add mailbox database copy »
Conclusion
In this article, you learned how to remove a mailbox server from a DAG configuration. It’s essential to remove the mailbox database copies before removing the member server from DAG. If you don’t do that first, an error shows up that the mailbox server cannot be removed from Database Availability Group.
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Hello Ali,
Thanks for your Great article,
We have a DAG member “mailbox01″crashed and got removed from ADSI Edit so it can’t be found in our AD already. ( didn’t remove it from ECP but it didn’t show up in DAG already) but when we try to add a new member to the DAG a error message pop up shows The fully qualifiled domain name for node “mailbox01” could not be found.
tried the command
Remove-DatabaseAvailabilityGroupServer -Identity “DAG01-2016” -MailboxServer “EX01-2016” -ConfigurationOnly -Confirm:$false
but shows Exchange server “mailbox01” was not found
Is there another way to completely remove it from whole exchange environment.
Thanks in advance.
-Jason
Ali
Many Thanks for maintaining this site; impeccable presentation and valuable content.
Hi Ali, thanks for the great article.
I want to seek for your advice.
If I have 4 Exchange servers in a DAG, WitnessServer is on another MemberServer.
After I remove a ExchangeServer from the DAG, what is the impact to the WitnessServer process ?
Hi Marcus,
You can safely remove Exchange Server DAG members from DAG without impacting the witness server.
Hello Ali,
I have two Servers in a DAG and I want to remove one Server from DAG. For now, every time I shutdown one of the servers I get an HTTP ERROR 500 then after I enter my credentials to login into OWA or ECP. Am I going to kill both servers if I remove the one I want from the DAG?