A global healthcare compliance SaaS provider hosts its core patient-tracking application o… — AWS Certified Solutions Architect - Associate

A global healthcare compliance SaaS provider hosts its core patient-tracking application on Amazon EC2 instances in an Auto Scaling group (ASG) behind an Application Load Balancer (ALB). The application database is hosted on Amazon Aurora MySQL-Compatible Edition. The application is currently deployed in the $us-east-1$ Region. The provider needs to design a cross-region disaster recovery (DR) solution in the $us-west-2$ Region. The DR solution must meet a Recovery Time Objective (RTO) of $15$ minutes and a Recovery Point Objective (RPO) of $2$ minutes, while minimizing ongoing infrastructure running costs in the secondary Region during normal operations. Which architecture will meet these requirements at the lowest cost?

Configure Amazon Aurora Global Database with the primary cluster in us-east-1 and a secondary cluster in us-west-2. Deploy an ALB and an ASG in us-west-2 with the desired capacity set to 1 EC2 instance. Configure Route 53 failover routing with health checks. Use an AWS Systems Manager (SSM) Automation runbook to promote the secondary Aurora cluster and scale up the ASG during failover.Answer
B
Configure Amazon Aurora Global Database with the primary cluster in us-east-1 and a secondary cluster in us-west-2. Deploy an ALB and an ASG in us-west-2 with the desired capacity set to 0. Store an AWS CloudFormation template for the EC2 and ALB resources in Amazon S3. During a failover event, deploy the CloudFormation stack to provision the application tier, promote the secondary Aurora cluster, and update Route 53 routing.
C
Configure Route 53 Latency routing with health checks to distribute traffic between us-east-1 and us-west-2. Deploy the active EC2 application tier in both Regions. In us-west-2, deploy an Aurora MySQL Read Replica. If the primary Region fails, Route 53 will automatically direct all write traffic to the us-west-2 Read Replica to maintain write availability without database promotion overhead.
D
Perform hourly snapshots of the Aurora cluster in us-east-1 and copy them to an Amazon S3 Glacier Flexible Retrieval vault in us-west-2. In the event of a disaster, trigger an AWS Lambda function to initiate a Standard retrieval of the latest snapshot, restore the database to a new Aurora cluster in us-west-2, and spin up the EC2 application tier using a pre-configured AMI.

Answer

The correct architecture uses Amazon Aurora Global Database for real-time cross-region replication, combined with a scaled-down Warm Standby EC2 application tier (desired capacity set to 1 instance) in the recovery Region, managed via Route 53 failover routing and AWS Systems Manager (SSM) Automation runbooks.

The architecture that configures Amazon Aurora Global Database alongside a Warm Standby application tier (desired capacity of 1 EC2 instance) is the only option that meets both RPO and RTO requirements while minimizing costs. Aurora Global Database replicates data asynchronously within seconds, satisfying the

2

-minute RPO. Having a single pre-running EC2 instance ensures the application stack is initialized, allowing an SSM Automation runbook to promote the database and scale out the ASG in under

10

minutes, satisfying the

15

-minute RTO. Keeping the ASG at

1

instance during normal operations minimizes running costs compared to a fully provisioned Active-Active setup.

Step-by-Step Solution

Evaluate the database replication strategy to meet the

2

-minute RPO.

Amazon Aurora Global Database provides asynchronous replication with typical latency of less than

1

second, satisfying the RPO. Hourly snapshots or backup-restore methods are ruled out because they cannot guarantee data loss under

2

minutes.

Choosing a replication method that guarantees an RPO under

2

minutes is the primary constraint for the data tier.

Evaluate the compute tier deployment strategy to meet the

15

-minute RTO.

A Warm Standby strategy with a minimum of

1

running EC2 instance ensures the OS, dependencies, and configuration are active and running. A Pilot Light strategy with

0

running instances requires cold starts, CloudFormation stack deployment, and bootstrapping, which exceed the

15

-minute RTO limit.

The RTO is highly aggressive for cross-region failover, requiring pre-warmed compute resources that only need to scale out rather than be provisioned from scratch.

Assess the failover automation and routing mechanism.

Route 53 active-passive failover routing policies dynamically redirect traffic based on health checks. AWS Systems Manager (SSM) Automation handles the orchestration of promoting the secondary Aurora cluster to primary and scaling up the EC2 Auto Scaling group.

Manual intervention takes too long and introduces errors. An automated runbook is required to meet the 15-minute RTO.

Key Concept

Cross-Region Disaster Recovery Strategies (Warm Standby vs. Pilot Light)

Estimated Time:3m 0s

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Key Concept

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