Question #862
A company operates a web application using an Application Load Balancer (ALB) and Docker containers hosted on Amazon ECS. The application data is stored in Amazon Aurora PostgreSQL, and the container images are stored in Amazon ECR. The company requires a disaster recovery plan with an RTO of no more than 24 hours and an RPO of no more than 8 hours.
Which of the following solutions is the MOST cost-effective way to meet these requirements?
Deploy identical ALB, ECS, and Aurora PostgreSQL resources in two regions using AWS CloudFormation. Enable continuous cross-region replication for the database. Use Amazon Route 53 with DNS failover to redirect traffic to the secondary region during a failure. Schedule ECR image replication to the secondary region every 8 hours.
Store container images in ECR in two regions. Schedule automated Aurora PostgreSQL backups every 8 hours and copy backups to the secondary region. In the event of a failure, use AWS CloudFormation to deploy ALB, ECS, and Aurora PostgreSQL resources in the secondary region, restore the latest backup, and update the DNS record to point to the secondary ALB.
Maintain a warm standby environment in a secondary region with ALB, ECS, and Aurora PostgreSQL resources running at reduced capacity. Use cross-region read replicas for the database and ECR image replication. Configure Route 53 health checks to failover traffic automatically during a failure.
Implement a pilot light architecture in a secondary region with minimal ALB and ECS resources. Create hourly Aurora PostgreSQL snapshots and replicate them to the secondary region. In the event of a failure, scale up ECS resources, restore the latest snapshot, and update DNS records manually.
Explanation
The correct answer is B because it balances cost-effectiveness with the RTO and RPO requirements. Aurora backups every 8 hours ensure the RPO is met, and ECR images are pre-replicated. In a disaster, CloudFormation deploys infrastructure on-demand, avoiding the cost of running redundant resources continuously. Options A and C involve higher costs due to active/passive or warm standby setups. Option D's pilot light requires some running resources and more frequent backups than needed, increasing costs. B's cold standby approach minimizes ongoing expenses while meeting recovery objectives.
Answer
The correct answer is: B