MLS-C01 Data Engineering Practice Question
Network Topology
A data engineer runs the AWS CLI command shown in the exhibit to find large log files in S3. The command returns an empty list, but the engineer knows there are files larger than 1 MB in that prefix. What is the MOST likely issue?
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
✓
The command does not paginate through all objects; only the first 1000 are returned
The `list-objects` command returns up to 1000 objects per call. If there are more than 1000 objects under the prefix, the command only examines the first 1000 objects. Since the engineer knows there are files larger than 1 MB, those files likely appear after the first 1000 objects. To find them, pagination is required (e.g., using `--page-size` or `--max-items` and `--starting-token`). Option A is incorrect because the JMESPath query is syntactically valid. Option C is incorrect because the engineer confirmed objects exist under the prefix. Option D is incorrect because `Size` is in bytes, so `1000000` correctly represents 1 MB.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The JMESPath query syntax is incorrect
Why it's wrong here
The query syntax is valid.
- ✓
The command does not paginate through all objects; only the first 1000 are returned
Why this is correct
list-objects limits to 1000 keys; use --max-items or pagination.
- ✗
The prefix is incorrect; there are no objects under that prefix
Why it's wrong here
The engineer knows there are objects.
- ✗
The Size value is in kilobytes, not bytes
Why it's wrong here
Size is in bytes; 1000000 is correct for 1 MB.
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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JA
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.