In a Microsoft Exchange Server 2013 Cumulative Update 6 environment, you receive a notification from Microsoft System Center Operations Manager (SCOM) or other monitoring tools stating that the ContentIndexRetryQueueSize value for a passive node of a database availability group (DAG) is very high.
Note To verify that you are experiencing this issue, you can implement the following steps:
From one of the Exchange Server 2013 servers in your environment, open the Exchange Management Shell (EMS).
Run the following command, replace <server> with a backed Exchange Server 2013 server in your environment:
Get-MailboxDatabase -server <server> | sort -Property name | Get-MailboxDatabaseCopyStatus | select name,status,content*
If you are experiencing this issue, the ContentIndexRetryQueueSize value for the passive databases will be between 100 and 300.
To resolve this issue, install Cumulative Update 7 for Exchange Server 2013.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.