Examine the status of the Database Availability Groups (DAGs)

[This topic is intended to address a specific issue called out by the Exchange Server Analyzer Tool. You should apply it only to systems that have had the Exchange Server Analyzer Tool run against them and are experiencing that specific issue. The Exchange Server Analyzer Tool, available as a free download, remotely collects configuration data from each server in the topology and automatically analyzes the data. The resulting report details important configuration issues, potential problems, and nondefault product settings. By following these recommendations, you can achieve better performance, scalability, reliability, and uptime. For more information about the tool or to download the latest versions, see "Microsoft Exchange Analyzers" at http://go.microsoft.com/fwlink/?linkid=34707.]  

Topic Last Modified: 2011-05-19

The Microsoft Exchange Analyzer Tool examines each Active Directory site that contains Microsoft Exchange Server 2010 Mailbox servers to determine the health and configuration of each Exchange 2010 Database Availability Group (DAG). To examine the DAGs, Exchange Analyzer performs the following operations in order:

  1. It runs the Get-DatabaseAvailabilityGroup cmdlet to obtain a listing of all the DAGs.

  2. It runs the following command to obtain a listing of every database that is included in each DAG:

    Get-MailboxDatabase | Where { $_.MasterServerOrAvailabilityGroup -eq "%DAGNAME%" }
  3. It runs the following command to determine the status of each database:

    Get-MailboxDatabaseCopyStatus -Identity %DAGDB%

Exchange Analyzer examines each database for every available copy status. For more information about the database copy statuses that are available, see "Monitoring High Availability and Site Resilience" (http://go.microsoft.com/fwlink/?LinkId=180465).

Additionally, Exchange Analyzer parses the following attributes to determine their current values:

  • CopyQueueLength

  • ReplayQueueLength

If the value for either attribute is 7 through 14, Exchange Analyzer generates a warning message. If the value for either attribute is 15 or greater, Exchange Analyzer generates an error message.

Exchange 2010 includes many tools and features that you can use to monitor Exchange when it is configured in a high-availability or site-resilient topology. Specifically, you can use the following two cmdlets to monitor high-availability or site-resilient configurations:

  • Get-MailboxDatabaseCopyStatus

  • Test-ReplicationHealth

In addition to these cmdlets, Exchange 2010 includes an event log stream that leverages the crimson channel capabilities in Windows Server. To collect data from these event channels, Exchange 2010 includes built-in scripts.

To manually test Exchange 2010 in a high-availability or site-resilient topology, you can perform the following actions:

  1. Configure at least two Exchange 2010 servers together with a DAG.

  2. Add a database to the DAG.

  3. Run the DAG health cmdlets that are mentioned in this topic together with the following tests:

    • Suspend a database copy

    • Dismount the database

    • Stop the replication service

    • Stop and disable one of the replication services, send some test e-mail, and then examine the copy or replay queue lengths

For More Information

For more information about the high-availability cmdlets that are available, see "High Availability Cmdlets" (http://go.microsoft.com/fwlink/?LinkId=180466).