I have a client with an existing Exchange 2007 organisation with approximately 200 users, all with reasonable size mailboxes. They wish to move to a new Exchange organisation in a completely new AD forest, on new hardware, in a different physical location. This new network is allready setup and waiting for use.
My question is, what is the best way to move these mailboxes to the new organisation? I fear I may need to use Export-Mailbox to export all these mailboxes to PST files, FTP them to the new location, create Mailboxes for every user and then re-import the data, which will be a very time consuming job, so if anyone has any better strategies, or tools to help they would be very much appreciated.
Even if there is no easy way to move the mailbox, do you have any recommendations to easily move AD accounts, even if the data has to be imported separately.
You should be able to follow most of the How to Transition from Single Forest to Cross-Forest procedure to make this happen. You don't have to worry about co-existance if you can do everything in one fell swoop.
Without using Identity Lifecycle Manager (as the procedure calls for), though you will have to handle adding an X.500 address for the old legacyExchangeDN attribute to each new account in the destination forest. Basically, you need the legacyExchangeDN from the old Exchange install to be added to the new recipients as an X500 format proxyAddress entry. It's not too bad to do, once you know what to do.
From an Exchange 2007 source to an Exchange 2007 destination you will be able to use a Cross-forest Move-Mailbox operation to help things out. Per this article, the cross-forest Move-Mailbox will detect an X.500 address proxy assigned to the destination account matching the source legacyExchangeDN. You'll need to have the legacyExchangeDN's already in place as X.500 proxies before doing the Move-Mailbox. That shudnow.net article also references a good list of properties to bring over when you migrate the users.