Microsoft 365 Certified: Administrator ExpertDeploy and manage a Microsoft 365 tenantHard

A Microsoft 365 administrator is preparing for a large-scale migration of user mailboxes from an on-premises Exchange Server 2016 environment to Exchange Online. The company requires a staged migration approach to minimize disruption and maintain seamless coexistence during the transition. Users must be able to access their mailboxes regardless of whether they are on-premises or in the cloud, and free/busy information must be shared between both environments. Which type of Exchange deployment should the administrator implement?

  1. ACutover migration
  2. BRemote move migration
  3. CHybrid deployment
  4. DStaged migration
Show answer & explanation

Correct answer: C. Hybrid deployment

A hybrid deployment provides the best solution for seamless coexistence and staged migration, allowing mailboxes to reside both on-premises and in Exchange Online. It ensures free/busy sharing, unified global address list, and consistent user experience during the transition, which is critical for a large-scale migration minimizing disruption.

Why the other options are wrong

  • A. Cutover migration is for small organizations (up to 2000 mailboxes) and involves moving all mailboxes at once, leading to potential disruption.
  • B. Remote move migration is a component of a hybrid deployment, not a standalone deployment type that provides full coexistence.
  • D. Staged migration (legacy method) is for Exchange 2003/2007 and doesn't provide the full coexistence features (like free/busy, unified GAL) of a hybrid deployment.

Exchange Hybrid Deployment

A configuration that integrates an on-premises Exchange organization with Exchange Online, creating a single, unified environment for email and collaboration during migration and for long-term coexistence.

  • Provides seamless mailbox moves between on-premises and cloud.
  • Enables shared free/busy, unified Global Address List (GAL).
  • Offers a consistent user experience during migration.

Memory trick: Hybrid deployment is like building a bridge between your on-premises castle and your cloud kingdom, allowing everyone to travel freely.

More Deploy and manage a Microsoft 365 tenant questions