The answer is AWS DataSync with an on-premises agent, because it can transfer 50 TB over a 1 Gbps link within 5 days—theoretical maximum is 54 TB—while encrypting data in transit via TLS and at rest with S3 server-side encryption. This solution is the most cost-effective for large data transfer on-prem to S3 AWS DataSync, as it avoids the expense of physical appliances like Snowball Edge when the bandwidth window is sufficient. On the MLS-C01 exam, this question tests your ability to calculate transfer feasibility and distinguish between data movement services: a common trap is choosing Snowball Edge for any large volume, but here the 1 Gbps link makes DataSync cheaper and faster to deploy. Another trap is S3 Transfer Acceleration, which optimizes public internet uploads but cannot read from HDFS directly. Memory tip: “DataSync for data that fits the pipe; Snowball for data that doesn’t.”
MLS-C01 Data Engineering Practice Question
This MLS-C01 practice question tests your understanding of data engineering. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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 data engineer needs to transfer 50 TB of data from an on-premises HDFS cluster to Amazon S3. The data must be encrypted in transit and at rest. The on-premises network has a 1 Gbps connection to AWS. The transfer must complete within 5 days. Which solution is MOST cost-effective and meets the requirements?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use AWS DataSync with a DataSync agent installed on-premises to transfer the data to S3.
Option C is correct. With 1 Gbps, the maximum theoretical transfer in 5 days is about 54 TB (1 Gbps = 0.125 GB/s, 0.125 * 86400 * 5 = 54000 GB = 54 TB). So it is feasible. AWS DataSync can transfer data from HDFS via a private endpoint using the DataSync agent, with encryption in transit (TLS) and at rest (S3 SSE). Option A is wrong because S3 Transfer Acceleration only speeds up uploads over public internet, not from HDFS directly. Option B is wrong because Snowball Edge would be faster but more expensive for this volume that can fit in the time window. Option D is wrong because AWS Glue is for ETL, not data transfer.
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.
✗
Use S3 Transfer Acceleration to upload the data directly from HDFS to S3.
Why it's wrong here
Transfer Acceleration is for public internet, not for HDFS.
✓
Use AWS DataSync with a DataSync agent installed on-premises to transfer the data to S3.
Why this is correct
DataSync can transfer over network with encryption and is optimized for speed.
Related concept
Read the scenario before looking for a memorised answer.
✗
Order an AWS Snowball Edge device and copy the data to it, then ship it back.
Why it's wrong here
Snowball is cost-effective for large volumes but not necessary when network can handle it in 5 days.
✗
Use AWS Glue to read from HDFS and write to S3 in a continuous ETL job.
Why it's wrong here
Glue does not directly read from HDFS without a connector and is not optimized for bulk transfer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
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.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→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 startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
What to study next
Got this wrong? Here's your next step.
Identify which MLS-C01 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Data Engineering — This question tests Data Engineering — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Use AWS DataSync with a DataSync agent installed on-premises to transfer the data to S3. — Option C is correct. With 1 Gbps, the maximum theoretical transfer in 5 days is about 54 TB (1 Gbps = 0.125 GB/s, 0.125 * 86400 * 5 = 54000 GB = 54 TB). So it is feasible. AWS DataSync can transfer data from HDFS via a private endpoint using the DataSync agent, with encryption in transit (TLS) and at rest (S3 SSE). Option A is wrong because S3 Transfer Acceleration only speeds up uploads over public internet, not from HDFS directly. Option B is wrong because Snowball Edge would be faster but more expensive for this volume that can fit in the time window. Option D is wrong because AWS Glue is for ETL, not data transfer.
What should I do if I get this MLS-C01 question wrong?
Identify which MLS-C01 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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 →
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 engineer needs to move 50 TB of historical data from an on-premises Hadoop cluster to Amazon S3. The network bandwidth is limited to 100 Mbps. Which AWS service should be used to transfer the data most efficiently?
easy
A.Amazon S3 Transfer Acceleration to speed up the transfer.
✓ B.AWS Snowball Edge device to physically ship the data.
C.AWS Direct Connect to establish a dedicated network connection.
D.AWS Site-to-Site VPN to connect and copy data.
Why B: Option C is correct because AWS Snowball is designed for large data transfers over limited bandwidth. Option A is wrong because Direct Connect requires high bandwidth and doesn't physically move data. Option B is wrong because S3 Transfer Acceleration speeds up transfers over the internet but still limited by bandwidth. Option D is wrong because VPN is not efficient for 50 TB.
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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.
Question Discussion
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