AWS Certified Solutions Architect – Associate (SAA-C03) — Question 340

A company collects data from a large number of participants who use wearable devices. The company stores the data in an Amazon DynamoDB table and uses applications to analyze the data. The data workload is constant and predictable. The company wants to stay at or below its forecasted budget for DynamoDB.

Which solution will meet these requirements MOST cost-effectively?

Answer options

• A. Use provisioned mode and DynamoDB Standard-Infrequent Access (DynamoDB Standard-IA). Reserve capacity for the forecasted workload.
• B. Use provisioned mode. Specify the read capacity units (RCUs) and write capacity units (WCUs).
• C. Use on-demand mode. Set the read capacity units (RCUs) and write capacity units (WCUs) high enough to accommodate changes in the workload.
• D. Use on-demand mode. Specify the read capacity units (RCUs) and write capacity units (WCUs) with reserved capacity.

Correct answer: B

Explanation

For stable and predictable workloads, DynamoDB provisioned capacity mode is the most cost-effective choice because it allows you to specify exact RCUs and WCUs, avoiding the higher per-request pricing of on-demand mode. On-demand mode is designed for unpredictable workloads and does not allow you to manually specify or reserve RCUs and WCUs in the same manner. Standard-IA is intended for cold data storage, which does not fit the active analytical requirements of this scenario.