Tenant to Tenant Migration

Introduction

• For tenant-to-tenant M365 migrations, we need to decide on the architecture approach based on the scenario.
• Source Tenant: Contoso
• Desination Tenant: Fabrikam

Business Scenario	Architecture Scenario	Architecture Approach
I sold a business unit and brand identity Contoso users will continue to be known as user@contoso.com.	Tenant-to-tenant migration without rebranding Identities will migrate to a target tenant and will keep the existing domain as part of the migration.	Single-Event Migration - Almost everything is migrated in a single event. Higher risk, shorter timeline. - Avoid single-event migrations larger than 15,000 users or 7 TB of site content. - Data volumes, network bandwidth, and helpdesk capacity can be limiting factors to scale. Consider using an alternate temporary domain for a phased migration if you are unable to accommodate a single event.
I sold a business unit and the business unit will adopt the target company’s branding Contoso users will be known as user@fabrikam.com	Tenant-to-tenant migration with rebranding Identities will migrate to a new target tenant and will change the brand identity as part of the migration.	Single-event migration (same as above)
		Phased migration Gradual migration of users, services, and data. Source domains are not transferred. Users assume new target domains. Lower risk, longer timeline. Coexistence limitations can cause issues.
I need to split users across two tenants My company cannot use the registered (*.onmicrosoft.com) tenant name I’m moving from a commercial tenant to Microsoft Cloud for Government	Cloud tenant move Identities remain in the source tenant, but all users in the affected domain and all workloads are moved to a new cloud tenant.	Tenant move or split Similar to single-event migration, except this does not include migrating accounts to a new on-premises AD DS forest. For tenant splits, this approach is not intended for long-term coexistence. Migration event includes additional work to re-establish existing identities to the new tenant.