Examkin

Question

Difficulty: Very hardHigh Availability and Disaster Recovery Design

A financial technology company is designing a multi-region disaster recovery (DR) architecture for a core banking application deployed across two AWS Regions: us-east-1 (Primary) and us-west-2 (Secondary). The application runs on Amazon EC2 instances in private subnets behind a public Application Load Balancer (ALB) in each region. The application must achieve a Recovery Time Objective (RTO) of 3 minutes and a Recovery Point Objective (RPO) of 15 seconds. Under normal operations, user requests must be routed to the closest region to minimize latency, with read traffic served locally in each region, and all write operations executed against the primary database. The EC2 instances require redundant outbound internet access to download compliance updates, and internal services must resolve names consistently across both regions using a Route 53 Private Hosted Zone. Which of the following architectures meets these requirements while minimizing recovery time and complexity?

  1. Deploy an Amazon Aurora PostgreSQL Global Database with the primary cluster in us-east-1 and a secondary cluster in us-west-2, enabling write forwarding on the secondary cluster. Configure Route 53 Latency-based routing with associated health checks pointing to the public ALBs in both regions. For outbound internet access, deploy a NAT Gateway in each Availability Zone of the VPCs in both regions. Associate the Route 53 Private Hosted Zone with the VPCs in both us-east-1 and us-west-2.Answer
  2. B
    Deploy an Amazon RDS PostgreSQL Multi-AZ instance in us-east-1 and a cross-region read replica in us-west-2. To handle local read traffic and writes, direct the us-west-2 application instances to read from the local replica and use write forwarding to send writes to the Multi-AZ standby instance in us-east-1. Deploy a single NAT Gateway in each region to handle outbound internet access. Associate the Route 53 Private Hosted Zone with both the us-east-1 and us-west-2 VPCs.
  3. C
    Deploy an Amazon Aurora PostgreSQL Global Database with the primary cluster in us-east-1 and a secondary cluster in us-west-2, enabling write forwarding on the secondary cluster. Configure Route 53 Latency-based routing with associated health checks pointing to the public ALBs. For outbound internet access, deploy a NAT Gateway in each Availability Zone of the VPCs in both regions. Associate the Route 53 Private Hosted Zone with the us-east-1 VPC, and rely on VPC Peering and Transit Gateway routing to allow the us-west-2 VPC to resolve records in the Private Hosted Zone.
  4. D
    Deploy an Amazon Aurora PostgreSQL database in us-east-1 and configure cross-region AWS Backup replication to copy snapshots to us-west-2 every hour. In the event of a disaster, use AWS CloudFormation to spin up the application tier and restore the database from the copied snapshot in us-west-2. Deploy NAT Gateways in each Availability Zone in both regions, and associate the Route 53 Private Hosted Zone with both VPCs.

Answer

The architecture utilizing Amazon Aurora PostgreSQL Global Database with write forwarding, Route 53 latency-based routing with health checks, NAT Gateways in each Availability Zone of both regions, and Route 53 Private Hosted Zone associated with both VPCs.
The architecture leveraging Amazon Aurora PostgreSQL Global Database with write forwarding meets the low RTO and RPO requirements by utilizing physical cross-region replication (RPO < 1 second) and enabling database promotion in under a minute. Enabling write forwarding allows application instances in the secondary region to issue write statements that are forwarded to the primary region, while reading from local replicas. Deploying NAT Gateways in each Availability Zone prevents cross-AZ dependency for outbound traffic. Finally, associating the Route 53 Private Hosted Zone with the VPCs in both regions ensures consistent name resolution across the environment.

Step-by-Step Solution

1
Select a multi-region database solution that supports local reads, writes forwarded to the primary region, and replication speeds supporting a 15-second RPO.
Amazon Aurora PostgreSQL Global Database with write forwarding enabled on the secondary cluster satisfies these constraints by utilizing storage-level physical replication (RPO < 1 second).
Standard RDS replicas do not support write forwarding, and snapshot-based replication fails to meet the strict RPO.
2
Ensure high availability and fault tolerance for outbound internet access within private subnets.
Deploy a NAT Gateway in each Availability Zone across both regions.
Using a single NAT Gateway per region introduces a single point of failure if the hosting Availability Zone goes down.
3
Establish consistent cross-region internal DNS resolution.
Associate the Route 53 Private Hosted Zone with both the primary and secondary VPCs.
Private Hosted Zones do not resolve transitively over VPC peering or routing paths unless explicitly associated with the client VPCs.
4
Configure external DNS routing to minimize latency and automate failover within the RTO target.
Use Route 53 Latency-based routing with associated health checks pointing to the public Application Load Balancers.
This automatically detects regional degradation and shifts traffic to the alternate region within the 3-minute RTO limit.

Key Concept

Multi-Region High Availability and Disaster Recovery Design with Aurora Global Database and Route 53 Routing Policies
Estimated Time:3m 0s
Rate this question

Topics

High Availability and Disaster Recovery Design

More questions from this topic