Google Cloud Professional Cloud Database Engineer — Question 17

Your company is migrating the existing infrastructure for a highly transactional application to Google Cloud. You have several databases in a MySQL database instance and need to decide how to transfer the data to Cloud SQL. You need to minimize the downtime for the migration of your 500 GB instance. What should you do?

Answer options

• A. 1. Create a Cloud SQL for MySQL instance for your databases, and configure Datastream to stream your database changes to Cloud SQL. 2. Select the Backfill historical data check box on your stream configuration to initiate Datastream to backfill any data that is out of sync between the source and destination. 3. Delete your stream when all changes are moved to Cloud SQL for MySQL, and update your application to use the new instance.
• B. 1. Create migration job using Database Migration Service. 2. Set the migration job type to Continuous, and allow the databases to complete the full dump phase and start sending data in change data capture (CDC) mode. 3. Wait for the replication delay to minimize, initiate a promotion of the new Cloud SQL instance, and wait for the migration job to complete. 4. Update your application connections to the new instance.
• C. 1. Create migration job using Database Migration Service. 2. Set the migration job type to One-time, and perform this migration during a maintenance window. 3. Stop all write workloads to the source database and initiate the dump. Wait for the dump to be loaded into the Cloud SQL destination database and the destination database to be promoted to the primary database. 4. Update your application connections to the new instance.
• D. 1. Use the mysqldump utility to manually initiate a backup of MySQL during the application maintenance window. 2. Move the files to Cloud Storage, and import each database into your Cloud SQL instance. 3. Continue to dump each database until all the databases are migrated. 4. Update your application connections to the new instance.

Correct answer: B

Explanation

The correct answer is B because it uses the Database Migration Service with a Continuous job type, allowing for minimal downtime by sending real-time changes during the migration process. Options A and D involve manual processes that could lead to longer downtimes, while C's One-time migration is less efficient for minimizing downtime compared to the Continuous approach.