Azure Database Migration Service: Features and Pricing
Azure Database Migration Service (DMS) is a fully managed service designed to enable seamless migrations from multiple database sources to Azure data platforms with minimal downtime. Whether you are migrating SQL Server, MySQL, PostgreSQL, MongoDB, or Oracle databases to Azure, DMS provides assessment tools, guided migration workflows, and continuous data replication for near-zero-downtime cutover. EPC Group has used Azure DMS to migrate thousands of databases for enterprise clients, including large-scale consolidation projects involving 500+ databases.
Overview of Azure Database Migration Service
Azure Database Migration Service orchestrates the end-to-end database migration process, from pre-migration assessment through continuous data sync and final cutover. The service supports both offline migrations (one-time data copy with planned downtime) and online migrations (continuous replication with minimal cutover window), making it suitable for mission-critical databases that cannot tolerate extended outages.
DMS integrates with Azure Migrate for holistic migration planning, providing a single pane of glass that covers discovery, assessment, and execution. The assessment phase identifies compatibility issues, recommends target configurations, and estimates costs before any data movement begins.
- Offline migration: One-time data copy for databases that can tolerate a planned maintenance window
- Online migration: Continuous data replication with minimal cutover downtime (typically seconds to minutes)
- Pre-migration assessment: Compatibility analysis, SKU recommendations, and cost estimation
- Multiple source databases: SQL Server, MySQL, PostgreSQL, MongoDB, Oracle, and more
- Multiple target platforms: Azure SQL Database, Azure SQL Managed Instance, Azure Database for MySQL/PostgreSQL, Cosmos DB
Key Features
- Data Migration Assistant (DMA): Assess SQL Server databases for compatibility issues and feature parity before migration
- Azure SQL Migration extension: Integrated migration tooling within Azure Data Studio
- Continuous data sync: Change data capture (CDC) for real-time replication during online migrations
- Schema migration: Automatic schema conversion and deployment to target databases
- Validation: Post-migration data validation to ensure completeness and accuracy
- Multi-database projects: Migrate multiple databases in parallel within a single migration project
- Azure Migrate integration: Unified migration hub for databases, servers, web apps, and virtual desktops
- Self-hosted integration runtime: Connect to source databases behind firewalls without opening inbound ports
- Progress monitoring: Real-time migration status with per-table progress tracking
- Retry and resume: Automatic retry on transient errors and ability to resume interrupted migrations
Pricing
Azure Database Migration Service pricing depends on the migration scenario and deployment model.
Free Scenarios
- SQL Server to Azure SQL Managed Instance (online): Free with DMS
- SQL Server to Azure SQL Database (offline): Free with DMS
- SQL Server to SQL Server on Azure VMs: Free with DMS
- Pre-migration assessment with Data Migration Assistant: Always free
Standard Tier
- 1–4 vCore instance for general-purpose migrations
- Supports offline migrations for most source/target combinations
- No additional cost for the DMS instance (pay for compute resources)
Premium Tier (Online Migrations)
- 4 vCore instance optimized for continuous data replication
- Required for online (minimal downtime) migrations
- Approximately $0.404 per vCore per hour during active migration
- Supports MySQL, PostgreSQL, and MongoDB online migrations
- Recommended for mission-critical databases requiring near-zero downtime
Note that additional costs may include compute for the self-hosted integration runtime, Azure storage for staging data, and the target database instance itself. Our consultants help clients model the complete migration cost including temporary parallel-run expenses.
Supported Migration Paths
- SQL Server to Azure SQL Database: Offline migration with schema conversion and data validation
- SQL Server to Azure SQL Managed Instance: Online migration with near-zero downtime using log shipping
- SQL Server to SQL Server on Azure VMs: Lift-and-shift with DMS handling data copy and cutover
- MySQL to Azure Database for MySQL: Online migration with continuous binlog replication
- PostgreSQL to Azure Database for PostgreSQL: Online migration with logical replication
- MongoDB to Azure Cosmos DB: Online migration from MongoDB to Cosmos DB's MongoDB API
- Oracle to Azure SQL/PostgreSQL: Schema conversion with SQL Server Migration Assistant (SSMA) plus DMS for data
- Amazon RDS to Azure: Cross-cloud migrations from AWS RDS instances to Azure-managed databases
Integration with Other Azure Services
- Azure Migrate: Unified migration hub that coordinates DMS with server, web app, and VDI migrations
- Azure Data Studio: Azure SQL Migration extension for guided migration from within the IDE
- Azure SQL Database: Direct target with automatic performance tuning post-migration
- Azure SQL Managed Instance: Near-100% SQL Server compatibility for lift-and-shift migrations
- Azure Monitor: Track migration progress, errors, and performance through centralized monitoring
- Azure Active Directory: Secure access to DMS resources with RBAC and managed identities
Best Practices for Enterprise Migrations
- Always run assessment first: Use Data Migration Assistant to identify blocking issues before starting migration
- Plan for parallel operation: Run source and target databases in parallel during online migration to validate application compatibility
- Test cutover repeatedly: Rehearse the cutover process in a staging environment to minimize production risk
- Right-size the target: Use DMS SKU recommendations but validate with your own performance baselines
- Migrate in waves: Group databases by application dependency and migrate in coordinated waves
- Validate data completeness: Run checksums and row counts on all tables post-migration
- Plan rollback: Maintain the source database in read-only mode during the parallel-run period in case rollback is needed
- Document connection string changes: Prepare application configuration updates in advance for rapid cutover
Why Choose EPC Group for Database Migrations
With 28+ years of enterprise database consulting and thousands of successful migrations, EPC Group is the partner you need for complex database modernization projects. We have migrated SQL Server, MySQL, PostgreSQL, Oracle, and MongoDB databases for healthcare organizations, financial institutions, and government agencies—all with strict downtime windows and compliance requirements.
Our migration methodology includes comprehensive assessment, wave planning, parallel-run validation, automated cutover orchestration, and post-migration optimization. We do not just move your data—we ensure your applications perform better on the target platform than they did on the source.
Ready to Migrate Your Databases to Azure?
Contact our database migration architects for a free assessment of your current database environment. We will evaluate compatibility, estimate costs, and deliver a phased migration plan with defined downtime windows.
Frequently Asked Questions
How much downtime should I expect during a database migration?
For online migrations, the cutover window is typically seconds to minutes, depending on the final transaction log catch-up. For offline migrations, downtime equals the time to copy all data from source to target plus validation. EPC Group typically achieves sub-minute cutover windows for online migrations through careful rehearsal and automated cutover scripts.
Can I migrate from Oracle to Azure SQL Database?
Yes, but it requires a two-step process. First, use SQL Server Migration Assistant (SSMA) for Oracle to convert the schema and stored procedures. Then use Azure Database Migration Service to migrate the data. Schema conversion may require manual intervention for Oracle-specific features like PL/SQL packages, materialized views, and sequences. EPC Group has performed Oracle-to-Azure SQL migrations for enterprises looking to reduce Oracle licensing costs.
Is Azure Database Migration Service free?
Many migration scenarios are free, including SQL Server to Azure SQL Managed Instance (online) and SQL Server to Azure SQL Database (offline). For MySQL, PostgreSQL, and MongoDB online migrations, the Premium tier of DMS incurs a per-vCore-hour charge during active migration. Pre-migration assessment with Data Migration Assistant is always free.
Can I migrate databases from AWS RDS to Azure?
Yes. Azure Database Migration Service supports cross-cloud migrations from Amazon RDS for SQL Server, MySQL, and PostgreSQL to their Azure equivalents. The process uses native replication protocols (log shipping, binlog, logical replication) to provide online migration with minimal downtime. Network connectivity between AWS and Azure is established via VPN or ExpressRoute during the migration.
How do I handle application changes during migration?
During online migration, your application continues to use the source database while DMS replicates changes to the target. At cutover, you update application connection strings to point to the target database. We recommend using Azure Traffic Manager or connection string aliases to minimize cutover effort. EPC Group prepares detailed runbooks that script every step of the cutover process to ensure a smooth transition.