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Difficulty: MediumHigh Availability and Disaster Recovery Design

A company is designing a high availability and disaster recovery architecture for a critical logistics fleet tracking application. The application runs on Amazon EC2 instances in private subnets behind an Application Load Balancer (ALB) in a primary VPC in us-east-1. The database layer uses Amazon Aurora PostgreSQL with auto-scaled Aurora Replicas for read queries. Private EC2 instances must access external mapping APIs via a NAT Gateway. The design must support a secondary VPC in us-west-2 for disaster recovery. The solution must achieve a Recovery Point Objective (RPO) of 15 minutes, a Recovery Time Objective (RTO) of 1 hour, and minimize operational costs. Which two actions should the solutions architect take to meet these requirements?

  1. Configure Amazon Aurora Global Database to replicate data from the primary VPC in us-east-1 to the secondary VPC in us-west-2, and provision a low-cost, scaled-down Aurora Replica in us-west-2.Answer
  2. Configure Amazon Route 53 with an active-passive failover routing policy, using Route 53 health checks tied to the primary ALB to automatically redirect public traffic to the secondary ALB during a failover event.Answer
  3. C
    Maintain a single NAT Gateway in one Availability Zone of the primary Region, and configure all private subnets across both Availability Zones to route outbound internet traffic through this single gateway to minimize hourly charges.
  4. D
    Use AWS Backup to create daily snapshots of the database, copy them to the secondary Region, and restore the database to a new cluster in the secondary Region during a disaster recovery event.
  5. E
    Deploy an Amazon RDS PostgreSQL database in a Multi-AZ configuration in the primary Region, and configure the application to send read-heavy traffic to the standby instance in the secondary Availability Zone to scale read capacity.
  6. F
    Create a Route 53 Private Hosted Zone in the us-west-2 VPC to resolve the database's regional endpoint, without associating it with the primary us-east-1 VPC, and use it to route application database traffic.

Answer

Configure Amazon Aurora Global Database with a scaled-down replica in the secondary Region, and set up Route 53 active-passive failover routing with health checks pointing to the Application Load Balancers.
To meet the RPO of 15 minutes, database replication must be fast and reliable. Amazon Aurora Global Database provides sub-second replication latency to a secondary Region, and using a scaled-down instance class minimizes running costs while meeting the objectives. To meet the 1-hour RTO, DNS failover must be automated. Amazon Route 53 active-passive failover with health checks automatically detects a primary region failure and redirects traffic to the secondary Application Load Balancer.

Step-by-Step Solution

1
Analyze RPO and RTO requirements to select database replication and failover mechanisms.
Identify that a sub-second replication latency database (like Aurora Global Database) and automated DNS failover are required to meet the 15-minute RPO and 1-hour RTO.
Standard backups fail the RPO/RTO target, so active-passive replication is necessary.
2
Determine the database deployment strategy in the secondary Region.
Select Aurora Global Database with a scaled-down instance class in the target disaster recovery region to minimize cost.
This keeps costs low during normal operations while guaranteeing that replication remains up to date.
3
Set up external routing and health checks.
Configure Route 53 active-passive failover routing associated with Application Load Balancer health checks.
This automates the failover to the secondary Region within the 1-hour RTO without manual intervention.

Key Concept

Disaster Recovery strategies (Warm Standby/Pilot Light) require low-latency replication for short RPOs and automated DNS routing failover for low RTOs.
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Topics

High Availability and Disaster Recovery Design

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