Database Migration Service

Database Migration Service (DMS) is Google Cloud's fully managed service for migrating databases to GCP with minimal downtime. It supports continuous replication from source databases to Cloud SQL, AlloyDB, and Cloud Spanner, enabling a smooth transition from on-premises, other clouds, or self-managed instances.

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What Is Database Migration Service?

DMS provides a serverless, end-to-end migration pipeline that:

• Continuously replicates data from source to destination in near real-time.
• Minimises downtime — applications continue running during migration; you cut over when replication is caught up.
• Handles schema conversion — for heterogeneous migrations (e.g. Oracle to PostgreSQL), DMS includes schema mapping tools.
• Validates data — built-in validation ensures data integrity before and after cutover.
• Fully managed — no servers to provision or manage.

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Supported Migration Paths

Homogeneous Migrations (Same Engine)

Source	Destination
MySQL (on-premises, AWS RDS, Azure)	Cloud SQL for MySQL
PostgreSQL (on-premises, AWS RDS, Azure)	Cloud SQL for PostgreSQL
PostgreSQL	AlloyDB for PostgreSQL

Heterogeneous Migrations (Different Engine)