AWS Certified Solutions Architect – Associate (SAA-C03) — Question 390

A company wants to use the AWS Cloud to make an existing application highly available and resilient. The current version of the application resides in the company's data center. The application recently experienced data loss after a database server crashed because of an unexpected power outage.

The company needs a solution that avoids any single points of failure. The solution must give the application the ability to scale to meet user demand.

Which solution will meet these requirements?

Answer options

• A. Deploy the application servers by using Amazon EC2 instances in an Auto Scaling group across multiple Availability Zones. Use an Amazon RDS DB instance in a Multi-AZ configuration.
• B. Deploy the application servers by using Amazon EC2 instances in an Auto Scaling group in a single Availability Zone. Deploy the database on an EC2 instance. Enable EC2 Auto Recovery.
• C. Deploy the application servers by using Amazon EC2 instances in an Auto Scaling group across multiple Availability Zones. Use an Amazon RDS DB instance with a read replica in a single Availability Zone. Promote the read replica to replace the primary DB instance if the primary DB instance fails.
• D. Deploy the application servers by using Amazon EC2 instances in an Auto Scaling group across multiple Availability Zones. Deploy the primary and secondary database servers on EC2 instances across multiple Availability Zones. Use Amazon Elastic Block Store (Amazon EBS) Multi-Attach to create shared storage between the instances.

Correct answer: A

Explanation

Option A is correct because deploying application servers in an Auto Scaling group across multiple Availability Zones ensures high availability and scalability, while an Amazon RDS Multi-AZ deployment provides automated replication and failover to prevent data loss and eliminate single points of failure. Option B fails to provide high availability as it relies on a single Availability Zone. Options C and D are incorrect because read replicas are primarily for scaling reads rather than immediate high-availability failover, and EBS Multi-Attach is not designed to support shared-storage database clustering without specialized cluster-aware file systems.