07-26-2020 10:15 PM
07-26-2020 10:15 PM
We have two company's (each with their own forest and single domain) that have operated in a trusted ADDS forest configuration. Each forest contains their own respective mail system. One has on-premise Exchange 2013. The other ADDS forest has O365 and uses Azure AD Connect to sync on-premise ADDS users to o365. These mail systems are utilizing Galsync (enow) to support cross forest GAL's.
We are not (yet) using o365 SharePoint, one drive, or other 0365 services other than email. *We will later in the new named entity.
We are now going to merge these two environments (ADDS forest(s) / domain(s)) into a new named ADDS entity (forest and domain) - and new o365 tenant. This new named entity will utilize many of the o365 offerings.
I have migrated/merged trusted forests, and Exchange on-premise 2010/2013 systems together via ADMT and mailbox moves. This looks to be a bit more challenging.
Has anyone performed a similar migration/merge? Would they be willing to share how they did it?
Any insight, links, or thoughts are very much appreciated.
I found something similar in this forum on reddit -https://www.reddit.com/r/Office365/comments/93f4oq/cross_forest_office_365_migration/
Thanks in advance,
07-28-2020 04:59 PM
07-29-2020 09:17 PM
Yes, you are correct. We are going to change UPNs , Primary SMTPs etc and we will decommission Exchange 2013.
Would you recommend something about the process that might help?
08-02-2020 01:21 PM
Sorry for the late answer , i was quite engaged. So have you started yet ? One this i would like to point out is to carefully plan your Identities , just make clear which one is which and what aliases are on them
What about your PST files ? Are they holding a lots of GB ? In a similar case we uploaded all Data and made the Import Jobs from 365 Admin.
08-06-2020 12:37 PM
08-07-2020 02:08 PM
Well if you allow me to summarize
Verify domains in Azure or O365 , keep in mind it MAY take 24 hours to move from one Tenant to another , plan before hands and add extra waiting time just in case
Check external guest identities that they don't make duplicates with actual AD users
Add UPN Suffixes to your Domain/Forest
Install/Upgrade AD Connect , provision users on new Tenant
Add Authoritative Domains run Hybrid Wizard and check all domains , select centralized mail transport if you keep your MX onpremise
In the meantime export all PSTs and plan for the Import procedure with AzCopy
Let me know your thoughts !