An RDS for MySQL database must survive an Availability Zone failure with automatic failover and no changes to application connection code. Which configuration meets that?
Show answer and explanation
Answer: A
A Multi-AZ instance deployment keeps a synchronous standby in a different Availability Zone, and replication to it is transparent to clients. If the primary or its zone fails, RDS promotes the standby and repoints the same DNS endpoint, so the application reconnects without any code or configuration change. That automatic endpoint switch is what makes the failure invisible to the application.
Why the other options are wrong
- B. Read replicas use asynchronous replication and stay read-only until someone promotes them, so failover is neither automatic nor lossless.
- C. Copying snapshots gives a recovery point in another Region, but restoring from it takes time and creates a new endpoint.
- D. DynamoDB is a separate NoSQL service and cannot serve as a failover target for a MySQL database.
Exam tip. Automatic failover with an unchanged endpoint is Multi-AZ, not a read replica.