DEA-C01 DynamoDB capacity modes Practice Question
A company has an Amazon DynamoDB table with a provisioned write capacity of 1000 WCU. During a flash sale, the write traffic spikes to 5000 WCU for 10 minutes. The table is not auto-scaled. Which action should the data engineer take to handle the spike without throttling?
⚠ Common exam trap
Candidates often assume DAX can handle write spikes because it is a cache, but DAX only caches reads and does not buffer writes. The correct approach is to use on-demand capacity for unpredictable traffic spikes.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Convert the table to on-demand capacity mode before the sale.
The table is currently provisioned with 1000 WCU and cannot handle a spike to 5000 WCU. Converting to on-demand mode before the sale allows DynamoDB to automatically handle varying traffic without throttling, as on-demand capacity scales instantly to meet demand. Option D (auto-scaling) might not react quickly enough for a short 10-minute spike, and the table is not currently auto-scaled. Option C is incorrect because DAX is a read cache and does not buffer or improve write capacity. Option B is reactive and would not prevent initial throttling.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Convert the table to on-demand capacity mode before the sale.
Why this is correct
On-demand mode removes provisioned WCU entirely, so DynamoDB instantly accommodates the 5000 WCU burst without throttling. Since the table is not auto-scaled and 1000 WCU is fixed, switching before the flash sale is the only action that absorbs the spike.
- ✗
Set a CloudWatch alarm to increase provisioned capacity when write throttling occurs.
Why it's wrong here
A reactive CloudWatch alarm only fires after throttling has already begun, so requests during the 10-minute spike are still rejected; DynamoDB auto scaling likewise adjusts capacity on a lagging schedule. It suits steady, predictable growth where occasional brief throttling is tolerable, not an abrupt fivefold surge.
- ✗
Use DynamoDB Accelerator (DAX) to cache writes.
Why it's wrong here
DAX caches reads, not writes, so it cannot absorb 5000 WCU of write traffic; the table still throttles. It tempts because DAX reduces DynamoDB load, but that benefit applies to read-heavy workloads, whereas this spike is entirely write capacity.
- ✗
Enable auto-scaling with a target utilization of 70% and a maximum capacity of 5000 WCU.
Why it's wrong here
Auto-scaling reacts over minutes and cannot raise provisioned capacity to 5000 WCU quickly enough for a ten-minute spike, so throttling still occurs. It tempts because auto-scaling handles gradual or sustained demand growth, which is its correct use, but not an abrupt short burst.
Go deeper
Related to this question
About these practice questions
Courseiva writes every DEA-C01 question from scratch — 1,321 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DEA-C01 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DEA-C01 exam.