AWS Certified Solutions Architect – Professional (SAP-C02) — Question 453

A company needs to implement disaster recovery for a critical application that runs in a single AWS Region. The application's users interact with a web frontend that is hosted on Amazon EC2 instances behind an Application Load Balancer (ALB). The application writes to an Amazon RDS for MySQL DB instance. The application also outputs processed documents that are stored in an Amazon S3 bucket.

The company’s finance team directly queries the database to run reports. During busy periods, these queries consume resources and negatively affect application performance.

A solutions architect must design a solution that will provide resiliency during a disaster. The solution must minimize data loss and must resolve the performance problems that result from the finance team's queries.

Which solution will meet these requirements?

Answer options

• A. Migrate the database to Amazon DynamoDB and use DynamoDB global tables. Instruct the finance team to query a global table in a separate Region. Create an AWS Lambda function to periodically synchronize the contents of the original S3 bucket to a new S3 bucket in the separate Region. Launch EC2 instances and create an ALB in the separate Region. Configure the application to point to the new S3 bucket.
• B. Launch additional EC2 instances that host the application in a separate Region. Add the additional instances to the existing ALIn the separate Region, create a read replica of the RDS DB instance. Instruct the finance team to run queries against the read replica. Use S3 Cross-Region Replication (CRR) from the original S3 bucket to a new S3 bucket in the separate Region. During a disaster, promote the read replica to a standalone DB instance. Configure the application to point to the new S3 bucket and to the newly promoted read replica.
• C. Create a read replica of the RDS DB instance in a separate Region. Instruct the finance team to run queries against the read replica. Create AMIs of the EC2 instances that host the application frontend. Copy the AMIs to the separate Region. Use S3 Cross-Region Replication (CRR) from the original S3 bucket to a new S3 bucket in the separate Region. During a disaster, promote the read replica to a standalone DB instance. Launch EC2 instances from the AMIs and create an ALB to present the application to end users. Configure the application to point to the new S3 bucket.
• D. Create hourly snapshots of the RDS DB instance. Copy the snapshots to a separate Region. Add an Amazon ElastiCache cluster in front of the existing RDS database. Create AMIs of the EC2 instances that host the application frontend. Copy the AMIs to the separate Region. Use S3 Cross-Region Replication (CRR) from the original S3 bucket to a new S3 bucket in the separate Region. During a disaster, restore the database from the latest RDS snapshot. Launch EC2 instances from the AMIs and create an ALB to present the application to end users. Configure the application to point to the new S3 bucket.

Correct answer: C

Explanation

Option C is correct because creating an RDS read replica in a separate Region offloads the finance team's heavy queries to resolve performance issues while also serving as a low-latency disaster recovery target that can be quickly promoted. Replicating EC2 AMIs and using S3 Cross-Region Replication (CRR) ensures that both the compute and storage layers can be rapidly recovered in the target Region with minimal data loss. Other options are incorrect because you cannot register cross-region EC2 instances to a standard ALB (Option B), migrating RDS MySQL to DynamoDB requires a complete application redesign (Option A), and relying on hourly snapshots increases potential data loss compared to active replication (Option D).