The following event is logged in the Application log on each database availability group member in a Microsoft Exchange Server 2010 environment:
Product: Exchange Event ID: 2153 Source: MSExchangeRepl Message: The log copier was unable to communicate with server '<FQDN of remote server>'. The copy of database '<Database name>\<local server name>' is in a disconnected state. The communication error was: A timeout occurred while communicating with server '<FQDN of remote server>'. Error: The network read operation didn't complete within 15 seconds. The copier will automatically retry after a short delay.
This issue occurs if one of the following conditions is true:
A remote host does not process a log copy request correctly.
The Get-MailboxDatabaseCopyStatus cmdlet returns the Disconnected status for the database that is mentioned in the error.
When this issue occurs, you may not be able to run backups on the server.
The remote host may process the next log copy request correctly after few seconds.
To resolve this issue, install the following update rollup:
2579150 Description of Update Rollup 4 for Exchange Server 2010 Service Pack 1
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For more information about database availability groups, visit the following Microsoft website: