We are looking to merge two independent AD structures in to one new structure, and also move the in-house Exchange setup from one structure to the O365 setup of the other structure. Email wise there will be a single new domain to cover the new company. AD wise, I guess it makes sense to use the same domain for the new merged company. Problems ahead then!?!
So to make it easier to understand i guess
Company A has an O365 setup ran off their local AD via dirsync
Company B has an in-house Ex2007 box ran off their own local AD
In a short space of time we need to have Company A's O365 moved to a new primary email domain, and also have Company B's email migrated over to O365.
The AD merger from two old structures to one new structure doesn't have to be immediate, but if that the right way to sort the email then so be it.
So should we setup a new CompanyAB AD structure first on a new AD server, then merge Company A onto it and change the DirSync to match the new domain?
Then should we migrate Company B onto the new CompanyAB structure, and then migrate mailboxes to O365?
Any help would be much appreciated.