SOA-C03 practice question: Scaling RDS, Aurora and DynamoDB

Reliability and Business Continuity A free question from our original SOA-C03 practice exam. Try it, then open the answer to see why each option is right or wrong.

A logistics broker runs an Amazon Aurora MySQL cluster with one writer and one Aurora Replica. Freight-rate reports run from a reporting tool whose demand varies from a few users overnight to hundreds near month-end, and the replica's CPU then reaches 95 percent. The writer must not be affected by the reports. The broker wants read capacity to follow demand automatically. Which TWO actions should a CloudOps engineer take? (Choose two.)

Choose two answers.

A. Change the writer to a larger instance class each month-end and change it back afterward with a scheduled Lambda function.
B. Turn on storage autoscaling for the cluster so that Aurora adds I/O capacity to the replica when report demand rises.
C. Point the reporting tool at the cluster endpoint so that Aurora balances its queries between the writer and the replica.
D. Add an Aurora Auto Scaling policy that adds and removes Aurora Replicas to keep average replica CPU utilization near a target.
E. Point the reporting tool at the cluster's reader endpoint so that its connections are spread across all available Aurora Replicas.

Show the answer and explanation

Answers: D, E

A. Wrong: Scaling the writer does not move reports off it and briefly interrupts writes during each change. It also adds custom automation to maintain. Learn more: DB instance classes (opens in a new tab)
B. Wrong: Aurora storage grows automatically and has no storage autoscaling setting to turn on. Storage size is not the bottleneck here, replica CPU is. Learn more: Amazon Aurora storage (opens in a new tab)
C. Wrong: The cluster endpoint always connects to the current writer instance. Reports would run on the writer, which the broker wants to protect. Learn more: Amazon Aurora endpoint connections (opens in a new tab)
D. Right: Correct. Aurora Auto Scaling uses target tracking to change the number of Aurora Replicas. Replicas are added near month-end and removed when demand drops. Learn more: Amazon Aurora Auto Scaling with Aurora Replicas (opens in a new tab)
E. Right: Correct. The reader endpoint distributes connections among the replicas, including ones Aurora Auto Scaling adds. The tool never needs to know individual instance names. Learn more: Amazon Aurora endpoint connections (opens in a new tab)

Explanation

Aurora scales reads horizontally. Aurora Auto Scaling adds and removes replicas with a target tracking policy, and the reader endpoint spreads connections across whatever replicas exist. The cluster endpoint always points at the writer, so reports must use the reader endpoint to stay off it.

SOA-C03 practice question: Scaling RDS, Aurora and DynamoDB

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