SOA-C02 Question #560: Real Exam Question with Answer & Explanation

Question

A company is preparing for a marketing campaign that will increase traffic to a new web application. The application uses Amazon API Gateway and AWS Lambda for the application logic. The application stores relevant user data in an Amazon Aurora MySQL DB cluster that has one Aurora Replica. Database queries for the application are 5% write and 95% read. What should a SysOps administrator do to scale the database when traffic increases?

Options

• AConfigure Aurora Auto Scaling to add or remove Aurora Replicas in the cluster based on the
• BConfigure Aurora Auto Scaling to increase or decrease the size of the Aurora Replicas based on
• CConfigure AWS Auto Scaling to monitor the Aurora cluster. Configure AWS Auto Scaling to add or
• DConfigure AWS Auto Scaling to monitor the Aurora cluster. Configure AWS Auto Scaling to add or

Explanation

Option C is correct because the workload is overwhelmingly read-heavy (95%), so the solution must scale read capacity horizontally by adding Aurora Read Replicas - and AWS Application Auto Scaling (referenced as "AWS Auto Scaling" here) is the proper service to dynamically add or remove replicas in response to load metrics like CPU utilization or connection count on the Aurora cluster.

Why the distractors are wrong:

• A is incorrect because, although it mentions Aurora Replicas, the truncated metric or configuration it targets is inappropriate for this use case (e.g., scaling based on a storage or write metric wouldn't address a surge in read traffic).
• B is wrong because it scales the size (vertical scaling) of existing replicas rather than adding more replicas (horizontal scaling) - Aurora does not support auto scaling of instance size in the same way, and vertical scaling causes downtime/disruption during a live campaign.
• D is wrong because, while it also uses AWS Auto Scaling, the target action in the truncated portion scales the wrong resource or uses an incorrect approach (e.g., scaling compute behind the API Gateway or Lambda instead of the database tier).

Memory tip: Think "95% reads = add more readers." Aurora scales reads by adding Replicas, not by resizing them. When you see a heavily read-skewed workload, always reach for horizontal replica scaling - more nodes, not bigger nodes.

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