Quick Answer
The answer is to increase the EBS volume size attached to the core nodes. This directly resolves the disk space issue because EMR core nodes store intermediate data and HDFS blocks on their attached EBS volumes; expanding these volumes provides immediate additional storage without altering the cluster’s compute capacity. On the AWS Certified Data Engineer Associate DEA-C01 exam, this question tests your understanding of how to scale storage independently from compute in EMR, a common scenario when dealing with shuffle data or large intermediate outputs. A frequent trap is confusing instance type changes (which affect vCPU and memory) with storage scaling, or assuming Spot Instances add disk capacity. Remember the memory tip: “Core nodes need disk, not a bigger chip”—when disk runs out, grow the EBS, not the instance.
This DEA-C01 practice question tests your understanding of data operations and support. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 is monitoring an Amazon EMR cluster and notices that the cluster is running out of disk space on the core nodes. Which action can be taken to resolve this issue?
Reduce the retention period of data stored on HDFS
Why wrong: May not be acceptable and doesn't add capacity.
Change the core node instance type to a compute-optimized type
Why wrong: Compute-optimized types may have less disk.
Increase the EBS volume size attached to core nodes
More EBS capacity directly adds disk space.
Use Spot Instances for core nodes
Why wrong: Spot Instances are cheaper but do not increase disk.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Increase the EBS volume size attached to core nodes
Option A is correct because increasing the volume size of EBS attached to core nodes provides more storage. Option B is wrong because changing instance type affects memory/CPU, not disk. Option C is wrong because Spot Instances are cheaper but do not add disk. Option D is wrong because reducing data retention is not always feasible and may lose data.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
Reduce the retention period of data stored on HDFS
Why it's wrong here
May not be acceptable and doesn't add capacity.
Change the core node instance type to a compute-optimized type
Why it's wrong here
Compute-optimized types may have less disk.
Increase the EBS volume size attached to core nodes
Why this is correct
More EBS capacity directly adds disk space.
Related concept
Read the scenario before looking for a memorised answer.
Use Spot Instances for core nodes
Why it's wrong here
Spot Instances are cheaper but do not increase disk.
Common exam traps
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
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.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
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
Identify which DEA-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.
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FAQ
Data Operations and Support — This question tests Data Operations and Support — Read the scenario before looking for a memorised answer..
The correct answer is: Increase the EBS volume size attached to core nodes — Option A is correct because increasing the volume size of EBS attached to core nodes provides more storage. Option B is wrong because changing instance type affects memory/CPU, not disk. Option C is wrong because Spot Instances are cheaper but do not add disk. Option D is wrong because reducing data retention is not always feasible and may lose data.
Identify which DEA-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.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 20, 2026
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.
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