Answer: Use the Google Cloud Console or gcloud CLI to manually create a new failover replica from backup.

In a Cloud SQL for MySQL environment, if a read replica instance becomes unavailable, the system does not automatically create a new replica. You need to manually intervene to ensure high availability and data consistency. Option A suggests creating a new clone database, which is not the correct approach for restoring a read replica. Option B is the correct action because creating a new failover replica from a backup ensures that you have a new read replica that is up-to-date with the primary instance. Option C is incorrect because the system does not automatically create a new replica. Option D is also incorrect because starting the original primary instance does not address the issue of the read replica being unavailable. The correct approach is to manually create a new failover replica from a backup to ensure the read replica is working.

Author: LeetQuiz Editorial Team