Question 718 of 1,711
DEA-C01 Data Store Management Practice Question
A company is designing a data store for IoT sensor data that is written once and never updated. The data must be stored with high durability and low cost. Which TWO AWS storage services are most suitable? (Choose TWO.)
⚠ Common exam trap
Many exam-takers choose DynamoDB (D) for its scalability and low latency, overlooking that the question emphasizes low cost and write-once immutability, where S3 and Glacier Deep Archive are orders of magnitude cheaper per GB stored.
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 S3
Amazon S3 is correct because it provides 99.999999999% (11 9's) durability, is designed for write-once-read-many (WORM) workloads, and offers low-cost storage tiers suitable for IoT sensor data that is never updated. S3's object storage model and lifecycle policies allow automatic transition to colder storage, making it ideal for immutable data at scale.
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 ElastiCache
Why it's wrong here
ElastiCache is for caching, not durable long-term storage.
- ✗
Amazon EBS
Why it's wrong here
EBS is block storage for EC2, not cost-effective for IoT data archival.
- ✓
Amazon S3
Why this is correct
S3 provides 99.999999999% durability and low cost for infrequently accessed data.
- ✗
Amazon DynamoDB
Why it's wrong here
DynamoDB is optimized for frequent reads/writes, not for cheap archival of immutable data.
- ✓
Amazon S3 Glacier Deep Archive
Why this is correct
Glacier Deep Archive offers the lowest cost for data that is rarely accessed and can tolerate retrieval times of hours.
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
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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.
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