Hey all,
So I'm in a bit of a pickle with my Exchange design and am trying to figure out if there's a way to migrate mailboxes across forests where Linked mailboxes are being used. I've done a bit of reading and have noted stuff like preparing the move request in AD, etc. But I'm wondering if someone can break it down for me.
The above is a OneNote diagram of how we have moved over time. Please forgive my sloppy handwriting but I hope it gets the point across. I will text it out here as well:
Original Design
The original design of the domains when I joined the company were fabrikam and contoso. Contoso is a domain that sits entirely in the "DMZ". Fabrikam was the internal AD forest where most services and users authenticated to. In Contoso, there are 2 domain controllers, the "Front End" Exchange Server (Edge Transport), and the "Back End" server, which is CAS/Mailbox.
There is a forest trust between contoso and fabrikam where "Linked Mailboxes" are created in Contoso, and then the LinkedMasterAccount is set to Fabrikam.
Migration/Hybrid Design
Due to the fact that these two domains were configured massively inappropriately, riddled with security holes as well as strange permissions configurations, the decision was made to create a new internal AD domain. In my OneNote, I've labeled this 'specialbank.com'.
A long while ago we migrated users from Fabrikam to SpecialBank via trusts. To facilitate access to Exchange, a new trust was created between Contoso and SpecialBank to allow us to update the LinkedMasterAccount parameter to the new Specialbank domain.
We have most of our users authenticating to their mailboxes via SpecialBank, while the mailboxes still reside in Contoso.
Migration from Exchange 2007 to Exchange 2013
I am attempting to now figure out the best way to migrate the mailboxes from Contoso to a new set of Mailbox servers in SpecialBank. This will also be an upgrade from Exchange 2007 (Current) to an Exchange 2013 installation. The latest Service Packs and CUs are installed in both.
What would be the best procedure to move these mailboxes? To my knowledge, the current best practice/recommended way is to perform a user/SID migration from Contoso to SpecialBank. But I already have accounts in SpecialBank that users are actively using.
I'm not opposed to doing a simple PST export from Contoso to SpecialBank, but we're looking at around 120 mailboxes. So I'm trying to make my life a little easier instead of spending a weekend here.
If I try to do it in batches, I need to figure out how to handle autodiscover and CAS. Since I'm creating an entirely new Exchange environment, I'm trying to limit what I place in the existing configuration. But I'm not opposed to setting up something temporarily if I need to in order to make the migration transparent to users.
Can anyone help?