What is the best approach to enhance the resilience of a MySQL deployment?

Choosing to replace a single instance MySQL deployment with Cloud SQL configured for high availability is the best approach to enhance resilience. Cloud SQL is a fully managed database service that offers built-in high availability configurations which automatically manage failover processes, backups, and patching, thus reducing the risk of downtime due to hardware or software failures.

High availability in Cloud SQL is typically achieved through a primary and a standby instance setup. This ensures that if the primary instance becomes unavailable for any reason, the system can seamlessly failover to the standby instance, maintaining availability of the database. This level of redundancy and automatic management significantly enhances the resilience of the database deployment compared to traditional single instance setups, where downtime can lead to service interruptions while recovery efforts are made.

Other options do not provide the same level of resilience. Using a single instance MySQL on Compute Engine, even with read-only replicas, does not offer automatic failover, thus presenting single points of failure. Replicating data from a single instance MySQL to Cloud SQL may improve some aspects of resilience but still relies on the single MySQL instance, which can cause downtimes if that instance fails. The option that suggests switching to Cloud SQL for redundancy without extra configuration lacks the assurance that the setup will be efficiently