AZ-305 Designing Microsoft Azure Infrastructure Solutions Exam

Design and Configure Azure Database Migration Service

Overview of Azure Database Migration Service

Azure Database Migration Service (DMS) is a fully managed solution designed to help you move your databases from on-premises or cloud environments to Azure with minimal downtime and end-to-end validation. It supports both homogeneous migrations (like SQL Server to Azure SQL Managed Instance) and heterogeneous migrations (such as Oracle to Azure SQL Database). This service aims to centralize migration tasks, reducing risk while ensuring data integrity, performance alignment, and compatibility requirements are met.

Choosing the Appropriate Target

To recommend the ideal target for migration, it is crucial to analyze the characteristics of the source database and how they map to the Azure Platform as a Service (PaaS) offerings. Some key considerations include:

• Feature compatibility: Assess if instance-level features, cross-database queries, and SQL Agent jobs are supported.
• Performance requirements: Determine the necessary compute size, I/O throughput, and service tier.
• Business continuity needs: Evaluate the requirement for built-in high availability and read scale-out options.

Based on this analysis, you may recommend Azure SQL Database for modern cloud-native applications or Azure SQL Managed Instance for scenarios requiring near-complete SQL Server compatibility.

Configuring Azure Database Migration Service

Setting up DMS involves creating a migration project and choosing between online and offline migration modes. The main steps for configuration include:

• Provisioning a DMS instance in Azure and configuring the Azure-SSIS Integration Runtime if needed.
• Creating a migration project in the Azure portal and selecting both the source and target connection endpoints.
• Running the pre-migration assessment wizard to identify any compatibility issues and validate schema mapping.
• Choosing offline mode for simpler cutovers or online mode for continuous data replication to minimize downtime.

DMS also facilitates the migration of instance-level objects and extended features. You can migrate:

• SQL Agent jobs: Only T-SQL steps are supported while SSIS-based jobs need to be scripted and redeployed.
• Logins and groups: SQL logins are supported by default; Windows logins can be enabled through Microsoft Entra ID access.
• SSIS packages: Redeployed from SSISDB to the Azure-SSIS runtime.
• SSRS reports: Converted to Power BI paginated reports using the RDL Migration Tool.

Migrating Data with Minimal Downtime

After the initial data load, DMS can continuously apply transaction logs or differential backups (in online mode), tracking progress in the Azure portal. Key validation and cutover tasks include:

• Monitoring replication status and checking error logs.
• Running data consistency checks and performing final schema comparisons.
• Executing a controlled failover or cutover during a maintenance window.
• Utilizing failover groups for cross-region replication, ensuring high availability and disaster recovery.

This thorough approach ensures that database migrations meet minimal downtime, data integrity, and performance alignment expectations in enterprise Azure deployments.