Question 945 of 1,711
DEA-C01 Data Store Management Practice Question
A data engineer needs to store time-series sensor data from thousands of IoT devices. The data is written once, read frequently for the last 24 hours, and rarely accessed after 30 days. Which storage solution is MOST cost-effective?
⚠ Common exam trap
Test-takers frequently choose Amazon S3 with lifecycle policies (Option D) because they associate S3 with cost-effective storage, but they overlook the requirement for frequent reads of recent data, which S3 cannot serve with low latency without additional caching layers, and they miss that Timestream is the only AWS service natively designed for time-series data with automatic tiering and retention.
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
✓
Amazon Timestream with a 30-day retention policy.
Amazon Timestream is purpose-built for time-series data, offering automatic storage tiering where recent data resides in memory for fast queries and historical data is moved to a cost-optimized magnetic store. A 30-day retention policy aligns perfectly with the requirement to keep data accessible for frequent reads over the last 24 hours while automatically expiring older data, minimizing storage costs without manual intervention.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Amazon Redshift with automatic compression and distribution keys.
Why it's wrong here
Redshift is more expensive and not ideal for high-frequency writes of small records.
- ✗
Amazon DynamoDB with TTL to expire data after 30 days.
Why it's wrong here
DynamoDB is optimized for key-value access and can be costly for high write throughput of sensor data.
- ✓
Amazon Timestream with a 30-day retention policy.
Why this is correct
Timestream is designed for time-series data, with cost-effective tiered storage and built-in analytics.
- ✗
Amazon S3 with lifecycle policies to transition to S3 Glacier after 30 days.
Why it's wrong here
S3 does not natively support time-series queries; additional services like Athena are needed, increasing cost and complexity.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Last reviewed: Jun 24, 2026
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.