Assume that you have mailbox database copies on database availability group (DAG) member servers in a Microsoft Exchange Server 2010 environment. In this situation, the following messages are logged on the Exchange Server 2010 DAG member servers:
Log Name: Application Source: MSExchangeRepl Date: Date Event ID: 2174 Task Category: Service Level: Warning Keywords: Classic User: N/A Computer: Computer Description: The log copier for database <Mailbox Database> detected that the end of log is changing from generation 0xy(z) to 0xy-1(z-1). This passive copy will reinitialize to ensure that a log stream reset is handled correctly.
Log Name: Application Source: MSExchangeRepl Date: Date Event ID: 2153 Task Category: Service Level: Error Keywords: Classic User: N/A Computer: Computer Description:The log copier was unable to communicate with server FQDN of the Active Server. The copy of database Mailbox Database\Local Server is in a disconnected state. The communication error was: An error occurred while communicating with server Active Server. Error: Unable to read data from the transport connection: An established connection was aborted by the software in your host machine. The copier will automatically retry after a short delay.
Note When this issue occurs, a backup process that is running may fail.
This issue occurs because the generated number of the log file is incorrectly determined when the log file is replicated from the active mailbox database copy to passive copies. If a block mode overflow occurs at the end of a log file generation, the generated number cannot be confirmed with the current generated number.
To resolve this issue, install the following update rollup:
2645995 Description of Update Rollup 1 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 high availability and site resilience, visit the following Microsoft website: