5.1.3. Design a Migration Solution

💡 First Principle: A successful cloud migration is a strategic process of discovery, planning, execution, and optimization that enables organizations to transition workloads to the cloud with minimal disruption, risk, and cost.

Scenario: You are designing a migration plan for a legacy enterprise application that includes several Virtual Machines, a large SQL Server database, and shared file servers on-premises. The business requires minimal downtime for the database and a phased migration approach for the VMs.

A migration solution facilitates the secure and efficient transfer of on-premises workloads, applications, and data to the Azure cloud, enabling organizations to leverage cloud benefits while minimizing disruption.

Key Design Considerations:

• Assessment and Planning: Evaluate existing infrastructure and dependencies. Define migration goals and create a detailed plan. Use Azure Migrate for discovery.
• Migration Strategy: Choose between rehost (lift-and-shift), refactor, re-architect, rebuild, or replace.
• Data Migration: Select appropriate tools for transferring data, considering volume and downtime tolerance. Use Azure Data Box for large offline transfers, or Azure Database Migration Service (DMS).
• Application Migration: Migrate applications, ensuring compatibility and performance.
• Network Connectivity: Establish secure connectivity between on-premises and Azure (Azure VPN Gateway, Azure ExpressRoute).
• Security and Compliance: Integrate security controls and ensure compliance throughout the migration.
• Azure Migration Services: Leverage Azure Migrate for discovery, assessment, and migration. Utilize Azure Database Migration Service (DMS) for specialized database migrations.

⚠️ Common Pitfall: A "lift-and-shift" migration with no plan for future modernization. While rehosting is a valid first step, stopping there means leaving most of the cloud's benefits—like elasticity and managed services—on the table.

Key Trade-Offs:

• Speed of Migration vs. Cloud Optimization: The fastest migration strategies (like rehosting) provide the fewest cloud-native benefits. The most beneficial strategies (like refactoring) take the most time and effort.

Reflection Question: How does designing a migration solution (including assessment, strategy choice, data migration, and application migration tools like Azure Migrate and DMS) fundamentally facilitate the secure and efficient transfer of on-premises workloads to Azure, enabling cloud benefits while minimizing disruption and risk?