Article ID: 2743761 - View products that this article applies to.
Consider the following scenario:
Note The expected behavior is for as few mailbox servers as possible to be removed from the failover cluster for the DAG. This is so that the remaining mailbox servers can still communicate with one another. Therefore, the DAG can continue to run if the cluster still has quorum.
To resolve this issue, install the following update rollup:
(http://support.microsoft.com/kb/2785908/ )Description of Update Rollup 5 version 2 for Exchange Server 2010 Service Pack 2
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about DAGs, go to the following Microsoft website:
Understanding database availability groupsFor more information about a similar issue, click the following article number to view the article in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/2552040/ )A Windows Server 2008 R2 failover cluster loses quorum when an asymmetric communication failure occurs
(http://go.microsoft.com/fwlink/?LinkId=151500)for other considerations.
Article ID: 2743761 - Last Review: December 14, 2012 - Revision: 3.0