DEA-C01 Data Store Management Practice Question
Which TWO actions can help optimize Amazon S3 storage costs for a data lake? (Choose two.)
⚠ Common exam trap
Many candidates confuse cost optimization for storage (reducing stored data cost) with cost optimization for data transfer or retrieval, leading them to select options like S3 Select or Transfer Acceleration that address different cost dimensions.
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
✓
Use S3 Intelligent-Tiering for unpredictable access patterns
Option B is correct because S3 Intelligent-Tiering automatically moves objects between frequent and infrequent access tiers based on changing access patterns, eliminating retrieval fees and avoiding the cost of manual tiering when access is unpredictable. Option E is correct because S3 Lifecycle policies can transition aging objects to lower-cost storage classes such as S3 Glacier Instant Retrieval, Glacier Flexible Retrieval, or Glacier Deep Archive, directly reducing storage costs for cold data. Option A is not a cost optimization for a data lake because S3 Replication to another region incurs additional storage, request, and inter-region data transfer charges. Option C reduces data scanned and compute cost for querying, but it does not lower S3 storage costs. Option D speeds up uploads over long distances via AWS edge locations but adds a premium charge, so it increases rather than optimizes storage cost.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Enable S3 Replication to another region
Why it's wrong here
Cross-region replication duplicates every object into another region, doubling storage and adding request and transfer charges. It serves disaster recovery and latency reduction, not cost optimisation; lifecycle transitions to cheaper storage classes are what reduce data-lake spend.
- ✓
Use S3 Intelligent-Tiering for unpredictable access patterns
Why this is correct
S3 Intelligent-Tiering automatically moves objects between frequent and infrequent access tiers based on observed access patterns, charging a small monitoring fee. This satisfies the stem's unpredictable access constraint, since lifecycle policies require known patterns to schedule transitions reliably.
- ✗
Use S3 Select to retrieve only needed data
Why it's wrong here
S3 Select reduces data transferred and processed per request, cutting compute and retrieval charges, but it does not change storage class pricing, which dominates data-lake cost. It suits query-heavy access patterns on large objects, not the storage-cost optimisation the question targets.
- ✗
Enable S3 Transfer Acceleration
Why it's wrong here
Transfer Acceleration speeds uploads and downloads over long distances by routing through edge locations, but it adds a premium per-GB charge on top of standard transfer fees. It suits globally distributed uploads needing faster throughput, not storage-cost reduction.
- ✓
Implement S3 Lifecycle policies to transition objects to Glacier
Why this is correct
Lifecycle policies automatically transition ageing objects from S3 Standard to Glacier tiers, cutting storage cost per gigabyte for infrequently accessed data lake records. This directly satisfies the cost-optimisation requirement without manual intervention or application changes.
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 |
Go deeper
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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.