Moving a database from one environment, platform, or version to another while maintaining data integrity and minimizing downtime. Like carefully relocating a filing cabinet full of important documents to a new building without losing or damaging any files. Cloud providers offer managed migration services like AWS DMS, Azure Database Migration Service, Google Cloud Database Migration Service, and OCI Database Migration to automate and simplify this process.
A retail company migrates their on-premises Oracle database to Amazon RDS for PostgreSQL using AWS DMS, which handles the schema conversion and continuous data synchronization. The service allows them to test the migration in a staging environment first, then perform a cutover with minimal downtime — their application switches to the cloud database while AWS DMS ensures no orders are lost during the transition.
All four are managed services that help move databases between environments with tooling for assessment, migration execution, and (often) continuous replication to reduce downtime. AWS DMS focuses on heterogeneous and homogeneous replication and commonly pairs with AWS Schema Conversion Tool for engine changes. Azure Database Migration Service supports online/offline migrations to Azure data platforms. Google Cloud Database Migration Service supports migrations into Cloud SQL and AlloyDB (depending on source/target). OCI Database Migration supports migrations into Oracle Cloud database targets with online/offline options depending on the scenario.