GoogleGoogle Professional Cloud Architect (PCA) Certification·EN·Updated 5 Sep 2026
Migrate an on‑prem MySQL application to Compute Engine using Cloud SQL with minimal downtime, no data loss, and minimal code changes. Which cutover plan do you use?
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Correct answer: Use Cloud VPN to connect Compute Engine to the on‑prem MySQL server; stop the on‑prem app; start the Compute Engine app configured to read/write the on‑prem MySQL; configure Cloud SQL replica replication from the source; allow Cloud SQL replica connections on the source; finalize replication; when replication is caught up stop the Compute Engine app; promote the Cloud SQL replica to standalone; restart the Compute Engine app configured to use the Cloud SQL standalone instance..
Why this is the answer
The correct option provides a detailed, multi-step plan that ensures minimal downtime and no data loss. By initially pointing the Compute Engine app to the on-prem MySQL and then setting up Cloud SQL as a replica, you maintain service continuity while data is synchronized. Promoting the replica to a standalone instance after it's fully caught up allows for a quick, controlled cutover. The other options involve taking the application offline for an extended period to perform a full dump and restore, which does not meet the minimal downtime requirement. Some options also introduce unnecessary components like MySQL proxy or complex dual-write strategies that increase complexity and risk.