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Difficulty: Very hardMulti-AZ, Multi-Region Architectures and Disaster Recovery (DR)

A financial clearinghouse processes sensitive transactional data in its primary AWS Region (us-east-1). The current architecture consists of an Amazon Aurora PostgreSQL-Compatible Edition database cluster and an application tier running on Amazon EC2 instances in an Auto Scaling group behind an Application Load Balancer (ALB). The clearinghouse must implement a disaster recovery (DR) strategy in a secondary Region (us-west-2) to ensure business continuity. The DR solution must achieve a Recovery Point Objective (RPO) of less than 1 minute and a Recovery Time Objective (RTO) of less than 10 minutes, while minimizing ongoing compute costs. Which database and application deployment strategy should a solutions architect recommend to meet these requirements?

  1. Deploy an Amazon Aurora Global Database with the primary cluster in us-east-1 and a secondary cluster in us-west-2. In us-west-2, pre-deploy the ALB and an Auto Scaling group with the minimum capacity set to 1 instance. Configure Amazon Route 53 failover routing with health checks to direct traffic to the secondary Region, and automate the promotion of the secondary database cluster in the event of a primary Region failure.Answer
  2. B
    Deploy an Amazon Aurora Global Database with the primary cluster in us-east-1 and a secondary cluster in us-west-2. Create a launch template for the EC2 instances in us-west-2. Write an AWS Lambda function triggered by Amazon CloudWatch alarms to create the ALB, provision the Auto Scaling group from scratch, and promote the secondary database cluster only when a regional failover is initiated.
  3. C
    Configure cross-region database replication using an Amazon RDS PostgreSQL Read Replica in us-west-2. Deploy a fully provisioned Auto Scaling group behind an ALB in us-west-2. Use Route 53 latency-based routing to distribute traffic. In the event of a disaster, manually promote the read replica to a primary database instance and update the application configuration files with the new endpoint.
  4. D
    Configure daily backups of the Aurora cluster in us-east-1 and copy the snapshots to us-west-2, storing them in Amazon S3 Glacier Flexible Retrieval to minimize storage costs. Maintain a warm standby EC2 fleet behind an ALB in us-west-2. In the event of a disaster, initiate an expedited retrieval of the latest snapshot, restore the database cluster, and update Route 53 routing records.

Answer

Deploy an Amazon Aurora Global Database with the primary cluster in us-east-1 and a secondary cluster in us-west-2. In us-west-2, pre-deploy the ALB and an Auto Scaling group with the minimum capacity set to 1 instance. Configure Amazon Route 53 failover routing with health checks to direct traffic to the secondary Region, and automate the promotion of the secondary database cluster in the event of a primary Region failure.
The correct strategy uses Amazon Aurora Global Database to achieve an RPO of less than 1 second through storage-level replication. For the application tier, a Warm Standby approach (pre-deploying the Application Load Balancer and running a minimal Auto Scaling group capacity of 1 instance) ensures that the infrastructure is ready to accept traffic immediately and scale out, satisfying the 10-minute RTO. Route 53 failover routing with health checks automates the DNS switchover, and promoting the secondary Aurora cluster takes less than a minute.

Step-by-Step Solution

1
Analyze the RPO requirement of less than 1 minute.
Identify that daily snapshots (which have a 24-hour RPO) and standard RDS read replicas (which can experience high replication lag under write-heavy loads) are unsuitable. Amazon Aurora Global Database uses storage-level, dedicated physical replication with typical lag of less than 1 second, meeting the RPO.
Choosing the replication technology that guarantees minimal data loss is the first step in disaster recovery planning.
2
Analyze the RTO requirement of less than 10 minutes.
Determine that a Pilot Light strategy (where compute resources like ALBs and Auto Scaling groups are created from scratch) is too slow to guarantee recovery within 10 minutes due to resource provisioning and instance bootstrapping times. A Warm Standby strategy (where the ALB is pre-deployed and a minimum compute capacity is already running) is required to ensure immediate availability and fast scaling.
Computing provisioning times directly impact the recovery time (RTO), requiring pre-warmed compute components.
3
Evaluate routing and failover automation.
Confirm that Amazon Route 53 failover routing with health checks provides automated DNS redirection to the secondary Region. The promotion of the Aurora Global Database secondary cluster to primary can be automated via AWS Systems Manager or Lambda to execute within minutes.
Automated failover reduces manual operational steps, ensuring the RTO threshold is not breached during stress events.

Key Concept

Disaster Recovery (DR) Strategies (Warm Standby vs. Pilot Light) and Cross-Region Replication with Aurora Global Database
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Topics

Multi-AZ, Multi-Region Architectures and Disaster Recovery (DR)

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