DEA-C01 Data Operations and Support Practice Question
A data engineer is using Amazon Kinesis Data Firehose to deliver streaming data to an S3 bucket. The data is delivered in 5-minute intervals. However, the engineer notices that the data in S3 is often delayed by up to 30 minutes. Which configuration change would most likely reduce the delay?
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
✓
Decrease the 'Buffer interval' from 300 seconds to 60 seconds.
The buffer interval determines the maximum time Firehose will wait before delivering data, regardless of buffer size. Decreasing it from 300 to 60 seconds forces more frequent deliveries, reducing the delay. Option B (compression) reduces data size, which could slow buffer filling and potentially increase delay if the buffer size trigger is not met. Option C (increasing buffer size) would cause Firehose to wait longer for the buffer to fill, increasing delay. Option D (dynamic partitioning) affects data organization, not delivery frequency, so it does not reduce delay.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Decrease the 'Buffer interval' from 300 seconds to 60 seconds.
Why this is correct
Shorter buffer interval triggers more frequent deliveries.
- ✗
Enable compression (GZIP) on the Firehose delivery stream.
Why it's wrong here
Compression reduces file size, but buffer time still applies.
- ✗
Increase the 'Buffer size' from 5 MB to 50 MB.
Why it's wrong here
Larger buffer size may increase delay.
- ✗
Enable 'Dynamic partitioning' on the Firehose stream.
Why it's wrong here
Dynamic partitioning affects how data is organized, not delivery frequency.
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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Same concept, more angles
1 more way this is tested on DEA-C01
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A data pipeline uses Amazon Kinesis Data Firehose to deliver data to an Amazon S3 bucket. The delivery stream is configured with a buffer size of 5 MB and a buffer interval of 60 seconds. The team notices that the S3 objects are much smaller than 5 MB. What is the most likely explanation?
hard- ✓ A.The incoming data volume is low, so the 60-second buffer interval triggers delivery before the 5 MB buffer is filled.
- B.The S3 bucket has event notifications that split the objects.
- C.The S3 bucket has a lifecycle policy that transitions objects to Glacier.
- D.The delivery stream is using GZIP compression, which reduces the object size.
Why A: If the incoming data rate is low, the buffer interval (60 seconds) expires before the buffer size (5 MB) is reached, causing small objects. Option B is incorrect because S3 event notifications do not split objects; they are triggered by events but do not affect object size. Option C is incorrect because S3 lifecycle policies transition objects to Glacier, which does not affect object size during delivery. Option D is incorrect because GZIP compression reduces the object size after batching, but the buffer interval can still trigger delivery before the buffer is full, so it is not the most likely explanation.
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.