Q90 — AWS DOP-C02 Ch.3

Question 90 of 100 | ← Chapter 3

A company manages a web application running on Amazon EC2 instances behind an Application Load Balancer (ALB). The EC2 instances run in an Auto Scaling group spanning multiple Availability Zones. The application uses an Amazon RDS for MySQL DB instance to store data. The company has already configured an Amazon Route 53 CNAME record pointing to the ALB. A new corporate policy requires a geographically isolated disaster recovery (DR) site with an RTO of 4 hours and an RPO of 15 minutes. Which DR strategy meets these requirements while minimizing changes to the application stack?

• A. Launch a copy environment of everything except Amazon RDS in a different Availability Zone. Create an RDS read replica in the new Availability Zone and configure the new stack to point to the local RDS DB instance. Add the new stack to the Route 53 record set using a failover routing policy with health checks.
• B. Launch a copy environment of everything except Amazon RDS in a different AWS Region. Create an RDS read replica in the new Region and configure the new stack to point to the local RDS DB instance. Add the new stack to the Route 53 record set using a latency routing policy with health checks.
• C. Launch a copy environment of everything except Amazon RDS in a different AWS Region. During an outage, copy and restore the latest RDS snapshot from the primary Region to the DR Region. Update the Route 53 record set to point to the ALB in the DR Region.
• D. Launch a copy environment of everything except Amazon RDS in a different AWS Region. Create an RDS read replica in the new Region and configure the new environment to point to the local RDS DB instance. Add the new stack to the Route 53 record set using a failover routing policy with health checks. During an outage, promote the read replica to become the primary instance. ✓

Correct Answer: D. Launch a copy environment of everything except Amazon RDS in a different AWS Region. Create an RDS read replica in the new Region and configure the new environment to point to the local RDS DB instance. Add the new stack to the Route 53 record set using a failover routing policy with health checks. During an outage, promote the read replica to become the primary instance.

Explanation

AWS disaster recovery strategies must satisfy geographic isolation, RTO, and RPO requirements. Geographic isolation requires cross-Region deployment; an RPO of 15 minutes demands near-real-time replication; and an RTO of 4 hours requires rapid, automated failover. AWS documentation states that cross-Region multi-AZ deployments with RDS read replicas are appropriate for this scenario. Option D deploys the replica environment across Regions, configures an RDS read replica, promotes it during failure, and uses Route 53 failover routing to automatically shift traffic—meeting both RPO and RTO with minimal application changes. Other options fail to simultaneously satisfy cross-Region isolation, rapid data recovery, or automated switching.