DMS (Database Migration Service)
💡 Definition
AWS Database Migration Service (DMS) helps you migrate databases to AWS quickly and securely. The source database remains fully operational during the migration, minimizing downtime to applications that rely on the database.
🔑 Key Concepts
- Homogeneous Migrations: Migrating between the same database engines (e.g., Oracle to Oracle on EC2 or RDS).
- Heterogeneous Migrations: Migrating between different database engines (e.g., Oracle to Aurora). Requires Schema Conversion Tool (SCT).
- Continuous Replication: Can replicate data continuously for ongoing synchronization.
⚙️ How it Works
- Replication Instance: You launch a DMS replication instance.
- Endpoints: Define source and target endpoints.
- Task: Create a migration task to move the data.
🎯 Use Cases
- Migration to Cloud: Moving on-premises databases to RDS or Aurora.
- Database Consolidation: Combining multiple databases into one.
- Continuous Replication: Syncing data between a production DB and a test DB.
💰 Pricing Model
- Replication Instance: Charged per hour.
- Data Transfer: Standard transfer rates apply.
- Free Usage: 6 months free for migrations to Aurora, Redshift, DynamoDB, or OpenSearch.
📝 Exam Tips (CLF-C02)
- Used for database migrations.
- Source stays online during migration.
- Supports Homogeneous (same engine) and Heterogeneous (different engine) migrations.
See Also: * RDS * Schema Conversion Tool (often tested together for heterogeneous migrations)