Question #1130
Which Amazon RDS feature ensures high availability by maintaining a synchronous standby replica in another Availability Zone, enabling automatic failover in the event of a primary instance failure?
Read replicas
Blue/green deployment
Multi-AZ deployment
Reserved Instances
Explanation
The correct answer is C. Multi-AZ deployment. Multi-AZ deployment creates a synchronous standby replica of the primary RDS instance in a different Availability Zone (AZ). This replica is continuously updated with data from the primary instance. In case of a primary instance failure, Amazon RDS automatically triggers a failover to the standby replica, minimizing downtime and ensuring high availability.
Why other options are incorrect:
- A. Read replicas: These are asynchronous replicas used for read scaling, not high availability. They do not support automatic failover.
- B. Blue/green deployment: A deployment strategy for minimizing downtime during updates, not related to high availability or failover.
- D. Reserved Instances: A billing option for cost savings, unrelated to high availability.
Key points to remember:
- Multi-AZ deployment is designed for high availability and automatic failover.
- Read replicas are for read scalability and asynchronous replication.
- Failover in Multi-AZ typically completes within 60–120 seconds.
Answer
The correct answer is: C