Recover a Database Availability Group Member Server


Applies to: Exchange Server 2010 SP3, Exchange Server 2010 SP2

If a Mailbox server that's a member of a database availability group (DAG) is lost or otherwise fails and is unrecoverable and needs replacement, you can perform a server recovery operation. Microsoft Exchange Server 2010 Setup includes the switch /m:RecoverServer that can be used to perform the server recovery operation. Running Setup with the /m:RecoverServer switch causes Setup to read the server's configuration information from Active Directory for a server with the same name as the server from which you're running Setup. After the server's configuration information is gathered from Active Directory, the original Exchange files and services are then installed on the server, and the roles and settings that were stored in Active Directory are then applied to the server.

Looking for other management tasks related to DAGs? Check out Managing Database Availability Groups.


If Exchange is installed in a location other than the default location, you must use the /TargetDir Setup switch to specify the location of the Exchange program files. If you don’t use the /TargetDir switch, the Exchange program files will be installed in the default location (%programfiles%\Microsoft\Exchange Server\V14).
To determine the install location, follow these steps:


  2. Navigate to the following location: CN=ExServerName,CN=Servers,CN=First Administrative Group,CN=Administrative Groups,CN=ExOrg Name,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=DomainName,CN=Com

  3. Right-click the Exchange server object, and then click Properties.

  4. Locate the msExchInstallPath attribute. This attribute stores the current installation path.

Use Setup /m:RecoverServer to recover a server

You need to be assigned permissions before you can perform this procedure. To see what permissions you need, see the"Mailbox database copies" entry in the High Availability Permissions topic.

  1. Retrieve any replay lag or truncation lag settings for any mailbox database copies that exist on the server being recovered by using the Get-MailboxDatabase cmdlet:

    Get-MailboxDatabase DB1 | Format-List *lag*
  2. Remove any mailbox database copies that exist on the server being recovered by using the Remove-MailboxDatabaseCopy cmdlet:

    Remove-MailboxDatabaseCopy DB1\MBX1
  3. Remove the failed server's configuration from the DAG by using the Remove-DatabaseAvailabilityGroupServer cmdlet:

    Remove-DatabaseAvailabilityGroupServer -Identity DAG1 -MailboxServer MBX1


If the DAG member being removed is offline and cannot be brought online, you must add the ConfigurationOnly parameter to the above command. If you use the ConfigurationOnly parameter, you must also manually evict the server from the cluster.

  1. Reset the server's computer account in Active Directory. For detailed steps, see Reset a Computer Account.

  2. Open a Command Prompt window. Using the original Setup media, run the following command:

    Setup /m:RecoverServer
  3. When the Setup recovery process is complete, add the recovered server to the DAG by using the Add-DatabaseAvailabilityGroupServer cmdlet:

    Add-DatabaseAvailabilityGroupServer -Identity DAG1 -MailboxServer MBX1
  4. After the server has been added back to the DAG, you can reconfigure mailbox database copies by using the Add-MailboxDatabaseCopy cmdlet. If any of the database copies being added previously had replay lag or truncation lag times greater than 0, you can use the ReplayLagTime and TruncationLagTime parameters of the Add-MailboxDatabaseCopy cmdlet to reconfigure those settings:

    Add-MailboxDatabaseCopy -Identity DB1 -MailboxServer MBX1
    Add-MailboxDatabaseCopy -Identity DB2 -MailboxServer MBX1 -ReplayLagTime 3.00:00:00
    Add-MailboxDatabaseCopy -Identity DB3 -MailboxServer MBX1 -ReplayLagTime 3.00:00:00 -TruncationLagTime 3.00:00:00

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