DEA-C01 Data Store Management Practice Question
A company is migrating an on-premises Apache Hadoop cluster to Amazon EMR. The cluster uses HDFS for storage. Which THREE features of Amazon EMR help reduce storage costs compared to on-premises HDFS? (Choose THREE)
⚠ Common exam trap
Watch out — candidates often confuse instance store volumes or EBS volumes as cost-saving alternatives, but the exam tests the understanding that S3-based storage with EMRFS is the primary mechanism for reducing storage costs in EMR by eliminating HDFS replication and enabling lifecycle management.
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
✓
Leverage Amazon S3 storage classes like S3 Standard-IA for older data.
Amazon S3 Standard-IA (Infrequent Access) offers lower storage costs than S3 Standard for data that is accessed less frequently, making it ideal for older or archival data in a Hadoop migration. By using S3 as the primary storage layer via EMRFS, you decouple compute from storage and avoid the replication overhead of HDFS (which typically uses 3x replication), significantly reducing storage costs.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Leverage Amazon S3 storage classes like S3 Standard-IA for older data.
Why this is correct
S3 storage classes allow cost optimization for infrequently accessed data.
- ✗
Use instance store volumes for intermediate data.
Why it's wrong here
Instance store volumes are ephemeral and do not provide cost savings for persistent storage.
- ✓
Enable automatic data compression in EMRFS.
Why this is correct
Compression reduces storage costs by reducing data size in S3.
- ✓
Use EMR File System (EMRFS) to store data in Amazon S3.
Why this is correct
S3 is cheaper than HDFS and provides durability and scalability.
- ✗
Attach Amazon EBS volumes to cluster nodes for persistent storage.
Why it's wrong here
EBS volumes add cost and are not a cost-saving feature.
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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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.