office 365 to office 365 tenant migration

Question

Folks ( exchange experts) I need your help with the below as the scenario is complicated.

I have an exisiting exchange hybrid model, many users are on office 365 are many users are on exchange servers. and i dont have a requirement to have all of the users under either exchange or office 365. ( Azure ad connect is running and HCW is there)

Now my requirement would be to migrate to a new office 365 tenant?

how can i achieve that knowing that hybrid model already exists between exchange server and my old office 365 and mail flow is working between both.

I was trying to plan for it but couldnt find a solution with no downtime.

worth mentioning that migrating back the o365 users to exchange servers, removing HCW and rerunning HCW on the new tenant is out of the question.

so i have thought about that approach:

• Create a new office 365 tenant
• Create a new azure ad connect instance without touching the old one and sync the same users to a new tenant
• Opt for a 3rd party migration tool and do the initial sync to migrate the data and gain some time

During a weekend, doing the following:

1. Pointing back MX records from O365 to exchange server old mail filter
2. Removing HCW which will remove the connectors and awhich will mean that Office 365 and exchange server now are different organizations which will lead to a downtime
3. Meanwhile, remove the domain from O365 and adding it to the new tenant and do the full migration of the data
4. Rerun HCW to target the new O365 tenant and to recreate the connectors
5. Remove the old azure ad connect
6. Point back the MX records to the new office 365 tenanat

Will this work folks? or you have another solution?

thank you in advance

Answer 1

Hi @ eg1995 ,

If you are concerned about downtime caused by the fact that Office 365 and Exchange servers are different organizations after removing HWC, I recommend that you could refer to the following migration order:

1. First, move all on-premises mailboxes and related information to the cloud.

2. Delete the hybrid configuration.

3. Migrate all users directly to another tenant with cross-tenant migration.

4. Rerun the hybrid deployment in the new tenant.

 

In addition, I found some similar cases performed by other users, I hope to give you some inspiration:

office365 - Migrate hybrid Office 365 to new tenant - Server Fault (Kindly note: Microsoft provides third-party contact information to help you find additional information about this topic. This contact information may change without notice. Microsoft does not guarantee the accuracy of third-party contact information.)

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