DEA-C01 Data Ingestion and Transformation Practice Question
A company uses Amazon Kinesis Data Firehose to deliver data to Amazon S3. The Firehose delivery stream has a buffer size of 64 MB and a buffer interval of 300 seconds. The data volume is 1 GB per minute, and the average record size is 1 KB. The data must be delivered to S3 within 5 minutes of ingestion. The engineer notices that some files are being delivered after 10 minutes. What is the most likely cause?
⚠ Common exam trap
The trap here is that candidates often focus on buffer size or interval settings, overlooking the S3 PUT request rate limit, which is a common cause of delivery delays in high-throughput Firehose-to-S3 pipelines.
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 S3 bucket is throttling PUT requests due to high throughput
Amazon S3 buckets have a default limit of 3,500 PUT requests per second per prefix. With a data volume of 1 GB per minute and an average record size of 1 KB, Firehose generates approximately 1,000,000 records per minute, resulting in roughly 16,667 PUT requests per second (since each 64 MB buffer yields about 65,536 records, and 1 GB/min ÷ 64 MB = ~15.6 buffers per minute, each requiring a PUT). This far exceeds the S3 PUT request limit, causing throttling (HTTP 503 Slow Down errors) and delivery delays beyond the 5-minute target.
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 buffer size of 64 MB is too small for the data volume
Why it's wrong here
64 MB is the default; with high volume, buffer fills quickly, so size is not the issue.
- ✗
The data is not compressed, causing larger file sizes
Why it's wrong here
Compression is not enabled by default but would only reduce size, not cause delays.
- ✗
The buffer interval of 300 seconds is too long
Why it's wrong here
Buffer interval is 5 minutes; data volume ensures buffer fills faster, so interval is not the cause.
- ✓
The S3 bucket is throttling PUT requests due to high throughput
Why this is correct
High PUT request rates can cause throttling, leading to retries and increased delivery time.
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 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.