The correct answer is to increase the buffer size to 50 MB and the buffer interval to 300 seconds. This works because Kinesis Firehose flushes data to S3 based on whichever condition is met first—buffer size or buffer interval—so the current 5 MB threshold causes frequent flushes that produce many small 2 MB files. By raising the buffer size to 50 MB, each flush accumulates more data, creating larger S3 objects, while the 300-second interval ensures latency stays under the 5-minute limit. On the AWS Certified Data Engineer Associate DEA-C01 exam, this scenario tests your understanding of Firehose buffering as a direct lever for controlling S3 object size, often with a trap where candidates mistakenly add Lambda transformations or compression instead of simply tuning buffer settings. A common memory tip: think of the buffer as a bucket—if you want bigger files, use a bigger bucket and wait longer before pouring it out.
DEA-C01 Data Store Management Practice Question
This DEA-C01 practice question tests your understanding of data store management. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company uses Amazon Kinesis Data Firehose to deliver streaming data to an Amazon S3 bucket. The data is JSON and each record is about 2 KB. The delivery stream is configured to buffer incoming data to 5 MB or 60 seconds, whichever comes first. The data engineering team notices that the S3 bucket contains many small files (average 2 MB), which makes subsequent processing inefficient. They need to reduce the number of small files without increasing the latency beyond 5 minutes. Which solution should they implement?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "first"
Why it matters: Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Increase the buffer size to 50 MB and the buffer interval to 300 seconds.
Option B is correct because increasing the buffer size to 50 MB and the buffer interval to 300 seconds directly addresses the root cause: the current 5 MB buffer size triggers a flush too frequently, producing many 2 MB files. By raising the buffer size to 50 MB, each flush will contain more data, resulting in larger S3 objects (up to ~50 MB uncompressed), while the 300-second interval ensures latency stays within the 5-minute requirement. This reduces the number of small files without requiring additional services or post-processing.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Enable compression (GZIP) on the delivery stream.
Why it's wrong here
Compression reduces storage size but not file count.
✓
Increase the buffer size to 50 MB and the buffer interval to 300 seconds.
Why this is correct
Larger buffer creates larger files within latency limit.
Clue confirmation
The clue word "first" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Use a Lambda function to merge small files after delivery.
Why it's wrong here
Adds complexity and potential additional cost.
✗
Decrease the buffer size to 1 MB and the buffer interval to 60 seconds.
Why it's wrong here
Would create even smaller files.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume compression (Option A) reduces file count, but compression only reduces file size, not the number of files; the real issue is the flush frequency controlled by buffer size and interval.
Detailed technical explanation
How to think about this question
Kinesis Data Firehose uses a buffer size (in MB) and buffer interval (in seconds) as flush triggers; the first condition met initiates a write to S3. The default buffer size is 5 MB, which is why records of ~2 KB accumulate to only ~2,500 records before flushing, yielding ~5 MB files (but compression or overhead can reduce actual file size). Increasing the buffer size to 50 MB allows up to ~25,000 records per file, significantly reducing file count, while the 300-second interval ensures that even with low data volume, files are delivered within the 5-minute latency window. Note that Firehose does not guarantee exact buffer sizes due to record boundaries and overhead, so actual file sizes may be slightly less than the configured buffer.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Data Store Management — This question tests Data Store Management — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Increase the buffer size to 50 MB and the buffer interval to 300 seconds. — Option B is correct because increasing the buffer size to 50 MB and the buffer interval to 300 seconds directly addresses the root cause: the current 5 MB buffer size triggers a flush too frequently, producing many 2 MB files. By raising the buffer size to 50 MB, each flush will contain more data, resulting in larger S3 objects (up to ~50 MB uncompressed), while the 300-second interval ensures latency stays within the 5-minute requirement. This reduces the number of small files without requiring additional services or post-processing.
What should I do if I get this DEA-C01 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "first". Order matters here. You are being tested on which action comes before the others — not which action is generally useful.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.