Slow mailbox move with Exchange 2010 SP1

I had complaints from some of my customers that moving users to Exchange 2010 SP1 system is slow and taking long time. In RTM Exchange was doing 5 parallel moves at a time due to the following settings:

RTM values:

MaxActiveMovesPerSourceMDB: This property indicates the number of mailboxes that can be moved on the source mailbox database at one time. The default value is 5 concurrent moves.

MaxActiveMovesPerTargetMDB: This property indicates the number of mailbox moves that can be moved on the target mailbox database at one time. The default value is 5 concurrent moves.

SP1 values:

MaxActiveMovesPerSourceMDB: This property indicates the number of mailboxes that can be moved on the source mailbox database at one time. The default value is 5 concurrent moves.

MaxActiveMovesPerTargetMDB: This property indicates the number of mailbox moves that can be moved on the target mailbox database at one time. The default value is 2 concurrent moves.

The change in MaxActiveMovesPerTargetMDB in SP1 means that we can only do 2 concurrent connections.

The workaround: check the values in the following file Exchange Server\V14\Bin\MSExchangeMailboxReplication.exe.config” and you can change MaxActiveMovesPerTargetMDB back to 5 to allow 5 concurrent moves.

Don’t forget to restart the Microsoft Exchange Mailbox Replication service and do this configuration change on all your CAS servers