Wednesday , August 12 2020

Database availability group must have quorum error

Decommissioning set of old Exchange 2013 servers had to export few mailboxes and
decommission them.But mailboxes are not mounting saying quorum not found. but for me the simplest way is to remove the Database Availability group completely and mount the databases and take the required data out via pst and decommission the same. So this might not be suitable for all scenarios.


Failed to mount database "MDB03". Error: An Active Manager operation failed. Error: An Active Manager operation
encountered an error. To perform this operation, the server must be a member of a database availability group, and the
database availability group must have quorum. Error: Unable to read from the cluster database. This may occur if the
server has recently been removed from the database availability group. [Server: MBEX01.azure365pro.com]
+ CategoryInfo : InvalidOperation: (MDB03:ADObjectId) [Mount-Database], InvalidOperationException
+ FullyQualifiedErrorId : [Server=MBEX02,RequestId=c41e871c-49e5-4a78-877f-51738b965ee1,TimeStamp=6/2/2020
6:11:51 AM] [FailureCategory=Cmdlet-InvalidOperationException] 7E29F70A,Microsoft.Exchange.Management.SystemConfig
urationTasks.MountDatabase
+ PSComputerName : mbex02.azure365pro.com

Removed all the Database Copies.

Using the configuration only switch and removed the mailbox servers from the DAG.
So that it will clear the DAG related entries from active directory.But this will not remove the dag member from real Cluster. Which we have to manually.

Remove-DatabaseAvailabilityGroupServer -ConfigurationOnly -MailboxServer SRV-HO-MBEX02 -Identity DAG2

As its a IP Less DAG,We cannot use the cluster manager to evice them. You got to use powershell.
To Evict the DAG Members.

Get-ClusterNode Node1 | Remove-ClusterNode -Force
Get-ClusterNode Node2 | Remove-ClusterNode -Force

Once the DAG Members are removed and it doesn’t have configuration on active directory. Now the databases will try to mount as a stand alone server.On reboot Databases mounted without DAG membership.

Now removed the DAG. using below commands. I have done the same steps when the cluster is completely messed up and none of the recovery options worked and we had to bring up the databases stand alone without DAG membership. Unless you understand the environment completely and don’t use this procedure without proper understanding of clusters and DAG attributes stored on Active Directory. It may cause real Damage to the environment.

About Satheshwaran Manoharan

Satheshwaran Manoharan is an Microsoft Office Server and Services MVP , Publisher of Azure365pro.com. Specialized in Office365 / Microsoft Exchange / Virtualization , Sathesh is an Messaging Expert supporting/Designing/Deploying many medium size businesses to large enterprises when it comes to Corporate messaging and Virtualization Infrastructure

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