DEA-C01 Data Operations and Support Practice Question
A company runs an Amazon EMR cluster processing data from S3. The data engineer notices that the cluster's task nodes are underutilized while core nodes are fully utilized. Which TWO steps should the engineer take to improve resource utilization?
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
✓
Increase the number of core nodes.
The core nodes are fully utilized, indicating a need for more processing capacity. Increasing the number of core nodes (Option B) adds more resources for HDFS and processing. Adding task nodes with Spot Instances (Option C) provides additional compute capacity without increasing HDFS storage, offloading work from core nodes. Option A (consolidating tasks) might reduce overhead but does not add capacity; Option D (reducing core nodes) would worsen utilization; Option E (moving HDFS from EBS to instance store) is not related to utilization and risks data loss.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Consolidate multiple small tasks into larger tasks.
Why it's wrong here
Task consolidation may not address core vs task imbalance.
- ✓
Increase the number of core nodes.
Why this is correct
More core nodes distribute processing load.
- ✓
Add more task nodes using Spot Instances.
Why this is correct
Task nodes can handle additional workload without increasing core nodes.
- ✗
Reduce the number of core nodes and increase the number of task nodes.
Why it's wrong here
Reducing core nodes may cause data loss if HDFS is used.
- ✗
Move HDFS data from EBS to instance store volumes.
Why it's wrong here
Instance store is ephemeral; not typically used for HDFS.
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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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.