A company is migrating an on-premises PostgreSQL database (5 TB) to Cloud SQL. They need minimal downtime and automated schema conversion if needed. Which GCP service should they use?
Trap 1: Datastream
Datastream provides change data capture for replicating ongoing changes into Cloud SQL, but it does not perform schema conversion or the bulk initial load of a 5 TB database. It is the right tool for continuous replication during cutover, not for the migration itself, so it fails the schema-conversion requirement.
Trap 2: Migrate for Compute Engine (formerly Velostrata)
Migrate for Compute Engine replicates VM workloads to Compute Engine, not database schemas into Cloud SQL, so it cannot perform the required schema conversion or minimal-downtime PostgreSQL migration. It is tempting because it excels at lift-and-shift VM migrations where source servers must run unchanged on Google Compute Engine.
Trap 3: Transfer Appliance
Transfer Appliance physically ships data to Cloud Storage, offering no direct Cloud SQL import, replication, or schema conversion, so downtime and conversion needs go unmet. It is tempting for bulk offline transfers of very large datasets where network bandwidth is the limiting factor and no live cutover is required.
- A
Database Migration Service (DMS)
Database Migration Service performs continuous replication from the on-premises PostgreSQL source to Cloud SQL, keeping downtime to a minimum during cutover. Its built-in schema conversion handles incompatible objects automatically, satisfying the automated conversion requirement for the 5 TB migration.
- B
Datastream
Why it fails: Datastream provides change data capture for replicating ongoing changes into Cloud SQL, but it does not perform schema conversion or the bulk initial load of a 5 TB database. It is the right tool for continuous replication during cutover, not for the migration itself, so it fails the schema-conversion requirement.
- C
Migrate for Compute Engine (formerly Velostrata)
Why it fails: Migrate for Compute Engine replicates VM workloads to Compute Engine, not database schemas into Cloud SQL, so it cannot perform the required schema conversion or minimal-downtime PostgreSQL migration. It is tempting because it excels at lift-and-shift VM migrations where source servers must run unchanged on Google Compute Engine.
- D
Transfer Appliance
Why it fails: Transfer Appliance physically ships data to Cloud Storage, offering no direct Cloud SQL import, replication, or schema conversion, so downtime and conversion needs go unmet. It is tempting for bulk offline transfers of very large datasets where network bandwidth is the limiting factor and no live cutover is required.