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Difficulty: MediumEnhancing Reliability and Disaster Recovery

A media company hosts a legacy video rendering application in the `us-west-2` Region. The architecture consists of Amazon EC2 instances in an Auto Scaling group behind an Application Load Balancer (ALB), and a multi-AZ Amazon Aurora PostgreSQL database cluster. The company needs to implement a disaster recovery (DR) strategy in the `us-east-1` Region. The business requires a Recovery Point Objective (RPO) of less than 1 minute and a Recovery Time Objective (RTO) of less than 15 minutes. Which configuration should a Solutions Architect recommend to meet these requirements with the lowest operational overhead?

  1. Configure an Amazon Aurora Global Database with the primary cluster in us-west-2 and a secondary cluster in us-east-1. Deploy a duplicate Application Load Balancer (ALB) and a warm standby Auto Scaling group with minimum capacity in us-east-1. Create Route 53 failover routing records pointing to the ALBs, associated with Route 53 health checks that monitor an application health endpoint. In a disaster, perform a managed failover of the Aurora Global Database and scale up the Auto Scaling group.Answer
  2. B
    Set up a cron job in us-west-2 to take hourly snapshots of the database, copy them to us-east-1, and write a script to restore the database from the latest snapshot during a disaster. Deploy the EC2 instances in us-east-1 using AWS CloudFormation after a disaster is declared. Use Route 53 failover routing to point to the Application Load Balancers.
  3. C
    Configure an Amazon Aurora Global Database with the primary cluster in us-west-2 and a secondary cluster in us-east-1. Deploy a duplicate Application Load Balancer (ALB) and a warm standby Auto Scaling group in us-east-1. Create Route 53 failover routing records pointing to the ALBs, but configure the Route 53 health checks to only verify the TCP port of the ALB without checking the underlying database or application status.
  4. D
    Configure an Amazon Aurora Global Database with the primary cluster in us-west-2 and a secondary cluster in us-east-1. Deploy a duplicate Application Load Balancer (ALB) and a warm standby Auto Scaling group in us-east-1. Create a Route 53 Private Hosted Zone (PHZ) in the primary account to resolve the database endpoint, but only associate the PHZ with the primary VPC in us-west-2.

Answer

Configure an Amazon Aurora Global Database with the primary cluster in us-west-2 and a secondary cluster in us-east-1. Deploy a duplicate Application Load Balancer (ALB) and a warm standby Auto Scaling group with minimum capacity in us-east-1. Create Route 53 failover routing records pointing to the ALBs, associated with Route 53 health checks that monitor an application health endpoint. In a disaster, perform a managed failover of the Aurora Global Database and scale up the Auto Scaling group.
The correct configuration uses Amazon Aurora Global Database, which utilizes storage-based replication with a typical lag of less than one second, satisfying the RPO requirement of under 1 minute. Utilizing a warm standby EC2 fleet with an ALB in the secondary region allows the application to be scaled up rapidly during a failover event. Configuring Route 53 failover records with application-level health checks ensures that failures at either the application or database level trigger DNS failover, meeting the RTO requirement of under 15 minutes.

Step-by-Step Solution

1
Evaluate the database replication strategy to satisfy the Recovery Point Objective (RPO) of less than 1 minute.
Aurora Global Database is selected because it uses storage-based, physical replication with typical lag under 1 second.
Cross-region snapshot copying or standard backup restorations are too slow and fail to meet the sub-minute RPO requirement.
2
Design the failover routing and health checking mechanism to achieve the Recovery Time Objective (RTO) of less than 15 minutes.
Route 53 failover routing is configured with health checks pointing to an application endpoint that validates database connectivity and application status.
If health checks only monitor the ALB TCP port, application or database failures won't trigger DNS failover, leaving the system in a degraded state.
3
Ensure DNS resolution is functional across regions.
Any Private Hosted Zone used for internal service discovery must be associated with the VPCs in both the primary and disaster recovery regions.
Without cross-VPC association, the application instances in the recovery region cannot resolve the database endpoints.

Key Concept

Disaster recovery planning requires mapping business RPO/RTO metrics with appropriate data replication and DNS failover strategies, ensuring end-to-end service availability.
Estimated Time:2m 0s
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Topics

Enhancing Reliability and Disaster Recovery