When a mailbox database copy has failed in an Exchange Server 2010 Database Availability Group (DAG) it may be necessary to reseed the mailbox server with the failed database copy.

Exchange 2010 DAG with a Failed Database Copy

To reseed the database copy launch the Exchange Management Shell on the server that is in a failed state.

First we need to suspend replication for the mailbox database copy on this server. Use the following command, specifying the mailbox database in the format “<mailbox database name>\<server name>”.

[PS] C:\>Suspend-MailboxDatabaseCopy -Identity "Mailbox Database 01\EX2"

Confirm
Are you sure you want to perform this action?
Suspending mailbox database copy "Mailbox Database 01" on server "EX2".
[Y] Yes  [A] Yes to All  [N] No  [L] No to All  [?] Help (default is "Y"): y

The mailbox database copy status will now change from “Failed” to “Failed and Suspended”.

Exchange 2010 Mailbox Database in Failed and Suspended State

Next we reseed the database with a new copy by issuing the following command.

[PS] C:\>Update-MailboxDatabaseCopy -Identity "Mailbox Database 01\EX2" -DeleteExistingFiles

The duration of the seeding process will depend on the size of the database and the speed of the network. When the update has completed it will automatically resume replication for the database copy. If you want to prevent automatic resume of replication use this command instead.

[PS] C:\>Update-MailboxDatabaseCopy -Identity "Mailbox Database 01\EX2" -DeleteExistingFiles -ManualResume