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Difficulty: EasyServerless and Automated Scaling Architectures for Cost Efficiency

A startup is deploying a new application that experiences highly unpredictable traffic. The application performs database read and write operations that spike suddenly for a few minutes and then drop to zero for hours. The startup wants to minimize costs and avoid paying for unused resources. Which Amazon DynamoDB capacity mode is the most cost-effective for this workload?

  1. On-demand capacity modeAnswer
  2. B
    Provisioned capacity mode with Auto Scaling
  3. C
    Provisioned capacity mode with high fixed capacity
  4. D
    Provisioned capacity mode with an Amazon SQS Standard queue to buffer writes

Answer

On-demand capacity mode
On-demand capacity mode is the most cost-effective choice for unpredictable, spiky workloads with long idle periods. It automatically scales to meet the sudden spikes instantly and incurs zero costs during idle hours since billing is based strictly on actual read and write request units consumed.

Step-by-Step Solution

1
Analyze the workload characteristics from the scenario.
The workload has highly unpredictable traffic, sudden spikes lasting a few minutes, and long periods of zero activity.
To determine the most cost-optimized and auto-scaled option, we must match workload patterns to AWS billing models.
2
Evaluate DynamoDB capacity modes against the workload patterns.
Provisioned capacity mode requires paying for a minimum threshold continuously, leading to idle costs. On-demand capacity mode scales instantly and charges only per request.
This identifies the configuration that eliminates costs during idle times and handles sudden spikes without throttling.

Key Concept

Amazon DynamoDB capacity modes for cost optimization
Estimated Time:1m 0s
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Serverless and Automated Scaling Architectures for Cost Efficiency