MLS-C01 Practice Question: Machine Learning Implementation and Operations
A company is using SageMaker to train a large NLP model. The training job is taking too long due to high I/O wait time. The data is stored as CSV files in S3. Which optimization should the company implement to reduce I/O wait time?
⚠ Common exam trap
It's easy for candidates to confuse data format optimizations (like RecordIO) or distribution strategies (like ShardedByS3Key) with the fundamental I/O bottleneck caused by downloading data to disk, leading them to overlook Pipe mode's direct streaming approach.
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 SageMaker Pipe mode to stream data directly from S3
SageMaker Pipe mode streams data directly from S3 into the training algorithm without first writing it to the local disk, eliminating the I/O wait time caused by downloading and decompressing CSV files. This is the most effective optimization for high I/O wait during training because it bypasses the bottleneck of writing large datasets to the instance's local storage.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Convert CSV files to RecordIO format
Why it's wrong here
RecordIO reduces file size but still uses File mode.
- ✓
Use SageMaker Pipe mode to stream data directly from S3
Why this is correct
Pipe mode avoids disk I/O by streaming data.
- ✗
Use SageMaker batch transform before training
Why it's wrong here
Batch transform is for inference, not training.
- ✗
Use SageMaker File mode with larger instance storage
Why it's wrong here
File mode still writes to disk, causing I/O wait.
- ✗
Use SageMaker ShardedByS3Key data distribution
Why it's wrong here
This distributes data but does not reduce I/O per instance.
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.