MLS-C01 Data Engineering Practice Question
A data engineering team is designing a data lake on Amazon S3. Raw data is ingested in JSON format and must be partitioned by year, month, and day. The team expects high query performance for recent data but infrequent queries for older data. The data is immutable. Which storage tier configuration minimizes costs while meeting performance requirements?
⚠ Common exam trap
Many candidates assume S3 Standard is required for all queryable data, overlooking that S3 Intelligent-Tiering provides the same low-latency performance as S3 Standard for all tiers (including Infrequent Access and Archive Instant Access) while automatically reducing storage costs for infrequently accessed data.
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 the entire data lake
S3 Intelligent-Tiering automatically moves objects between access tiers (frequent, infrequent, and archive instant access) based on changing access patterns, without performance impact or lifecycle management overhead. This matches the workload: recent data is queried frequently (automatic frequent tier), older data is queried rarely (automatic infrequent/archive instant tiers), and data is immutable, so no write/delete penalties apply. It minimizes cost by charging only for the tiers actually used, while maintaining millisecond latency for all tiers.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Store all data in S3 Standard, then move to S3 Glacier after 30 days using a lifecycle policy
Why it's wrong here
Glacier has retrieval delays that impact query performance for older data, even if infrequent.
- ✗
Store recent partitions in S3 Standard, older partitions in S3 One Zone-IA
Why it's wrong here
One Zone-IA is cheaper but less durable and may not be cost-optimal for infrequent queries; Intelligent-Tiering is better.
- ✗
Keep all data in S3 Standard because query performance is critical
Why it's wrong here
Standard is more expensive for infrequently accessed older data.
- ✓
Use S3 Intelligent-Tiering for the entire data lake
Why this is correct
Intelligent-Tiering automatically moves data between access tiers based on usage, optimizing cost without retrieval delays.
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 MLS-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 MLS-C01 exam.