AWS Certified Solutions Architect – Professional — Question 381

A mobile app has become very popular, and usage has gone from a few hundred to millions of users. Users capture and upload images of activities within a city, and provide ratings and recommendations. Data access patterns are unpredictable. The current application is hosted on Amazon EC2 instances behind an
Application Load Balancer (ALB). The application is experiencing slowdowns and costs are growing rapidly.
Which changes should a solutions architect make to the application architecture to control costs and improve performance?

Answer options

• A. Create an Amazon CloudFront distribution and place the ALB behind the distribution. Store static content in Amazon S3 in an Infrequent Access storage class.
• B. Store static content in an Amazon S3 bucket using the Intelligent Tiering storage class. Use an Amazon CloudFront distribution in front of the S3 bucket and the ALB.
• C. Place AWS Global Accelerator in front of the ALB. Migrate the static content to Amazon EFS, and then run an AWS Lambda function to resize the images during the migration process.
• D. Move the application code to AWS Fargate containers and swap out the EC2 instances with the Fargate containers.

Correct answer: B

Explanation

Using Amazon S3 with the Intelligent-Tiering storage class is ideal for unpredictable data access patterns because it automatically optimizes storage costs without operational overhead or retrieval fees. Placing Amazon CloudFront in front of both the S3 bucket (for static content) and the ALB (for dynamic content) improves global application performance through caching and lowers data transfer costs. Other alternatives like Amazon EFS are more expensive, and Infrequent Access storage classes can incur high retrieval fees if access patterns change unpredictably.