AWS Certified Solutions Architect – Professional — Question 453

Your company currently has a 2-tier web application running in an on-premises data center. You have experienced several infrastructure failures in the past two months resulting in significant financial losses. Your CIO is strongly agreeing to move the application to AWS. While working on achieving buy-in from the other company executives, he asks you to develop a disaster recovery plan to help improve Business continuity in the short term. He specifies a target Recovery Time
Objective (RTO) of 4 hours and a Recovery Point Objective (RPO) of 1 hour or less. He also asks you to implement the solution within 2 weeks.
Your database is 200GB in size and you have a 20Mbps Internet connection. How would you do this while minimizing costs?

Answer options

• A. Create an EBS backed private AMI which includes a fresh install of your application. Develop a CloudFormation template which includes your AMI and the required EC2, AutoScaling, and ELB resources to support deploying the application across Multiple- Availability-Zones. Asynchronously replicate transactions from your on-premises database to a database instance in AWS across a secure VPN connection.
• B. Deploy your application on EC2 instances within an Auto Scaling group across multiple availability zones. Asynchronously replicate transactions from your on- premises database to a database instance in AWS across a secure VPN connection.
• C. Create an EBS backed private AMI which includes a fresh install of your application. Setup a script in your data center to backup the local database every 1 hour and to encrypt and copy the resulting file to an S3 bucket using multi-part upload.
• D. Install your application on a compute-optimized EC2 instance capable of supporting the application's average load. Synchronously replicate transactions from your on-premises database to a database instance in AWS across a secure Direct Connect connection.

Correct answer: A

Explanation

Option A is correct because asynchronous replication over a VPN easily meets the 1-hour RPO, whereas uploading a full 200GB backup hourly over a 20Mbps connection (Option C) is mathematically impossible. Using a CloudFormation template to spin up compute resources on-demand satisfies the 4-hour RTO while keeping idle costs minimal compared to running active EC2 instances 24/7 (Option B). Additionally, Direct Connect (Option D) cannot be provisioned within the strict two-week timeline.