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

A Microsoft 365 administrator is planning to migrate a large number of user mailboxes from an on-premises Exchange Server 2016 environment to Exchange Online. The organization requires a seamless co-existence during the migration, allowing users to remain on-premises or in the cloud without disruption, and for mail flow to function bi-directionally. Which deployment model should the administrator choose?

  1. AStaged migration
  2. BIMAP migration
  3. CCutover migration
  4. DHybrid deployment
Show answer & explanation

Correct answer: D. Hybrid deployment

A hybrid deployment provides the necessary seamless co-existence and bi-directional mail flow between on-premises Exchange and Exchange Online, which is critical for large organizations requiring a gradual migration without disruption.

Why the other options are wrong

  • A. Staged migration is for larger organizations but is no longer supported for Exchange 2016/2019 and doesn't offer the same level of co-existence as hybrid.
  • B. IMAP migration only migrates mailbox data, not calendar, contacts, or co-existence features, and is generally for non-Exchange source systems.
  • C. Cutover migration is for small organizations (up to 2000 mailboxes) and results in downtime, not seamless co-existence.

Exchange Hybrid Deployment

A configuration that integrates an on-premises Exchange organization with Exchange Online, allowing for seamless co-existence, bi-directional mail flow, and gradual mailbox migration.

  • Provides a unified address book and calendaring.
  • Enables moving mailboxes between on-premises and cloud.
  • Requires the Exchange Hybrid Configuration Wizard (HCW).

Memory trick: Hybrid deployment: The best of both mail worlds.

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