Even if you performed mailbox moves with PowerShell in Exchange 2007, it's important that you understand that the process is completely different in Exchange 2010 SP1. There is a new set of cmdlets available for performing and managing mailbox moves, and the previously-used Move-Mailbox
cmdlet no longer exists. The architecture used by Exchange to perform mailbox moves uses a new concept known as move requests, which have been implemented in this latest version. In this recipe, you will learn how to manage move requests from the Exchange Management Shell.
To create a move request and move a mailbox to another database within the Exchange organization, use the New-MoveRequest
cmdlet, as shown next:
New-MoveRequest –Identity testuser –TargetDatabase DB2