Approach to migrate to GCC high from one forest/organization

Question

HI Team,

Wanted to know what is the best approach to migrate few of the users to GCC High. We have one forest/exchange organization but two separate tenant. One being commercial and one GCC High. Can AAD connect sync objects to two tenants? how mail flow would work? Is it possible to achieve having on exchange organization/forest?

Same domains can be registered to two tenant? one being GCC.

Please let us know if anybody has any experience like that and what is the usual approach.

Answer 1

Hi @GoodResource

We could refer to the official document which introduces about the supported topologies for Azure AD Connect, for your environment, refer to the single forest scenario:

The most common topology is a single on-premises forest, with one or multiple domains, and a single Azure AD tenant.

And official document also introduces about the below topology, which is currently in Public Preview. As the supported scenarios might still change, we recommend not deploying this topology in a production environment.

So, the answer for Can AAD connect sync objects to two tenants is No.

And Same domains can be registered to two tenant? is not supported as well.

And where are your users located now? Have you deployed the hybrid for your on-prem server and online environment now? If no, you could consider deploy hybrid with one of the online environment, and use the manual method to migrate users to another tenant (create user accounts in tanant firstly, then migrate/import their data files to the mailboxes )

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Answer 2

Hi,

Your scenario is just like the second picture I shared above, you could deploy it but it's not the suggested scenario by Microsoft.

Here is a related thread discussed the similar scenario: Is it possible to create a hybrid from on-premise Exchange to 2 separate 365 tenancies?

If you have one Active Directory and you configured 2 UPN Suffixes (Domains) on that Active Directory, and you need to have O365 tenant for each UPN suffix separately. Yes you can.

You have to install 2 VMs or servers in your on-premises infrastructure and Install 2 Azure AD Connect servers and link each Azure AD Connect server to one of the UPN suffix and link each Azure AD Connect server to an O365 tenant.

You have to be sure the following

1) you configured each Domain on a separate O365 tenant and the domain is verified.
2) To have the appropriate licenses>

And please also note that: Users in the on-premises Active Directory must not be synchronized to more than one tenant, and so Azure AD Connect must be configured using the Domain/OU filtering option to filter users from your on-premises directory to ensure they appear only in a single online Exchange tenant.

Details: September 2020 Hybrid Configuration Wizard Update

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