I've been tasked with merging the Exchange infrastructure of two businesses. Company B will be merged in to Company A.
Due to the size of the databases, geographical spread of the Exchange servers in Company B and speed of the links ( slow links to cities in India, Africa, etc ) this will be a staged migration.
My plan so far is this:
- Set up trusts between the forests
- Set up a shared SMTP address space
- Set up a shared GAL and free/busy availability across the businesses using FIM ( following http://www.msexchange.org/articles-tutorials/exchange-server-2010/migration-deployment/deep-dive-into-rich-coexistence-between-exchange-forests-part1.html
At this point, whilst nothing will be 'merged' as such, we should I believe have full interoperability between the businesses in terms of any user being able to send from any email domain, check free busy of any user, etc.
Next, would be to use the cross-domain mailbox move to move mailboxes over in stages - as we already have interoperability, nothing should change once we move a mailbox over.
Am I missing anything? Does this seem a good plan?