Increasing Exchange 2010 local move request limit

To increase this limit you can edit

%programfiles%\Exchange Server\V14\Bin\MSExchangeMailboxReplication.exe.config

and change the value for MaxActiveMovesPerTargetMDB to the number you want. Make sure you change it in both locations. I would probably not go over 5. 

Once you do that restart the Microsoft Exchange Mailbox Replication service and your moves should now do more at a time.

Source

http://osj42.blogspot.com/2011/11/increasing-exchange-2010-local-move.html