A financial services company is designing a disaster recovery (DR) solution for a critical transaction processing application. The primary infrastructure is deployed in the `us-east-1` Region, using Amazon EC2 instances in private subnets across three Availability Zones (AZs) and an Amazon Aurora PostgreSQL database. The application must remain highly available within the primary Region and resilient to regional failures. The DR solution in the `us-west-2` Region must achieve a Recovery Time Objective (RTO) of 15 minutes and a Recovery Point Objective (RPO) of 1 minute. The company wants to minimize ongoing running costs for the DR environment.
Which of the following architectures meets these requirements?
- ADeploy a single NAT Gateway in a public subnet in `us-east-1` to minimize NAT Gateway hourly charges. Set up an Amazon Aurora Global Database with the primary cluster in `us-east-1` and a secondary read-only cluster in `us-west-2`. Deploy a scaled-down Auto Scaling group of EC2 instances behind an Application Load Balancer (ALB) in `us-west-2`. Configure Route 53 Failover routing records with health checks to route traffic to `us-west-2` if `us-east-1` becomes unhealthy.
- BDeploy a NAT Gateway in each public subnet in the primary Region. Set up an Amazon Aurora Global Database with the primary cluster in `us-east-1` and a secondary read-only cluster in `us-west-2`. Create a Route 53 Private Hosted Zone (PHZ) in the primary account for the database endpoint and associate it only with the `us-east-1` VPC. Deploy a scaled-down Auto Scaling group of EC2 instances behind an ALB in `us-west-2`. Configure Route 53 Failover routing records with health checks to route public traffic to `us-west-2` during an outage.
- Deploy a NAT Gateway in each public subnet in the primary Region. Set up an Amazon Aurora Global Database with the primary cluster in `us-east-1` and a secondary read-only cluster in `us-west-2`. Deploy a scaled-down Auto Scaling group of EC2 instances behind an Application Load Balancer (ALB) in `us-west-2`. Configure Route 53 Failover routing records with health checks, directing traffic to the primary ALB under normal conditions and to the secondary ALB during a failover.Answer
- DDeploy a NAT Gateway in each public subnet in the primary Region. Configure AWS Backup to take hourly snapshots of the Aurora database and copy them to `us-west-2`. Deploy an AWS CloudFormation template in `us-west-2` that remains inactive until a disaster occurs. Upon a failover event, deploy the CloudFormation stack to launch the ALBs and EC2 instances, and restore the database cluster from the copied snapshot.
Answer
The correct architecture deploys a NAT Gateway per Availability Zone in the primary Region for high availability, sets up Amazon Aurora Global Database for sub-minute RPO cross-region replication, runs a scaled-down Auto Scaling group in the secondary Region to minimize costs, and routes traffic via Route 53 Failover routing records with health checks.
The correct architecture uses redundant NAT Gateways (one per Availability Zone) in the primary Region to ensure that a single AZ failure does not disrupt outbound internet access for the EC2 instances in private subnets. To satisfy the low RTO of 15 minutes and RPO of 1 minute, Amazon Aurora Global Database is used to continuously replicate data from the primary to the secondary Region with typical replication latency of under one second. Deploying a scaled-down Auto Scaling group in the secondary Region represents a Warm Standby disaster recovery strategy, which minimizes ongoing compute costs while allowing rapid scale-up. Route 53 Failover routing automatically shifts public traffic to the secondary Application Load Balancer if the primary Region endpoints become unhealthy.
Step-by-Step Solution
Key Concept
High Availability and Disaster Recovery Design
Estimated Time:2m 0s