Hybrid migration

Hybrid migration is a migration method that integrates an on-premises Exchange environment with Microsoft 365 or Office 365, creating a seamless and feature-rich experience for users and administrators. This approach allows for coexistence between the on-premises Exchange server and Microsoft 365, enabling organizations to gradually migrate mailboxes and maintain some mailboxes on-premises if needed.

Key Features of Hybrid Migration

1. Coexistence and Integration:

   • Provides a seamless user experience with unified GAL (Global Address List), shared calendars, and free/busy information between on-premises and cloud mailboxes.
   • Supports single sign-on (SSO) for a consistent login experience.

2. Flexible Migration:

   • Mailboxes can be moved to Microsoft 365 gradually, at your own pace.
   • Suitable for organizations with more than 2,000 mailboxes, but can also be used by smaller organizations needing a prolonged migration period.

3. Hybrid Configuration:

   • Requires setting up a hybrid configuration using the Hybrid Configuration Wizard (HCW), which assists in configuring and managing the hybrid deployment.
   • Involves setting up a hybrid server to handle secure mail flow between on-premises and Microsoft 365.

4. Pre-migration Tasks:

   • Verify that your domain is set up and configured correctly in Microsoft 365.
   • Prepare your on-premises Exchange environment, ensuring it meets the requirements for hybrid deployment.
   • Set up and configure Azure AD Connect for directory synchronization.

5. Migration Process:

   • Use the Hybrid Configuration Wizard to configure the hybrid deployment.
   • Move mailboxes to Microsoft 365 as needed, while keeping others on-premises.
   • Monitor and manage the hybrid environment through the Exchange admin center (EAC) and the Microsoft 365 admin center.

6. Post-migration Tasks:

   • Assign licenses to users with mailboxes in Microsoft 365.
   • Update DNS records to ensure proper mail flow.
   • Continue to manage both on-premises and cloud mailboxes using hybrid management tools.
   • Decommission the on-premises Exchange server if fully transitioning to Microsoft 365.

Advantages

• Seamless Experience: Provides a unified experience for end users, maintaining the look and feel of a single email environment.
• Flexibility: Allows for a gradual migration of mailboxes, providing flexibility and reducing the risk of disruptions.
• Advanced Features: Enables advanced features like shared calendar and free/busy information across environments.

Disadvantages

• Complexity: More complex to set up and manage compared to cutover or staged migration.
• Resource Intensive: Requires maintaining on-premises infrastructure alongside Microsoft 365, potentially increasing management overhead.

Ideal Scenarios for Hybrid Migration

• Large enterprises with more than 2,000 mailboxes that require a phased migration.
• Organizations needing to maintain some mailboxes on-premises due to regulatory or business requirements.
• Companies seeking to provide a seamless, integrated experience between on-premises and cloud environments during the migration period.

Summary

Hybrid migration is an ideal solution for large organizations looking to integrate their on-premises Exchange environment with Microsoft 365. It allows for a smooth, gradual transition, offering flexibility and advanced features like unified GAL, shared calendars, and SSO. Although it requires more setup and management compared to other migration methods, the hybrid approach provides a seamless user experience and enables organizations to move mailboxes at their own pace, making it suitable for complex and large-scale migrations.