DEA-C01 Data Store Management Practice Question
A company uses Amazon Redshift for its data warehouse. The data engineer notices that queries are running slower than expected. The system administrator reports that the cluster's disk space is 80% full. Which action should the engineer take to improve query performance?
⚠ Common exam trap
Many candidates confuse the symptom (slow queries) with a need for sort key optimization or vacuuming, when the root cause is insufficient storage capacity causing I/O bottlenecks, which only adding nodes can resolve.
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
✓
Add more nodes to the cluster to increase storage and compute capacity.
When a Redshift cluster's disk space is 80% full, query performance degrades because Redshift relies on large sequential I/O operations, and high disk utilization forces more random I/O and increases the likelihood of spilling to disk. Adding nodes increases both storage capacity and compute resources, directly alleviating the I/O bottleneck and improving query throughput. This is the recommended scaling action when disk space exceeds 70-80% utilization.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Redesign the sort keys to optimize query performance.
Why it's wrong here
Sort keys improve query performance but do not address disk space.
- ✗
Run the VACUUM command to reclaim space.
Why it's wrong here
VACUUM reclaims space but does not increase total capacity.
- ✓
Add more nodes to the cluster to increase storage and compute capacity.
Why this is correct
Adding nodes increases both storage and compute, improving performance.
- ✗
Enable concurrency scaling to handle more queries.
Why it's wrong here
Concurrency scaling adds compute resources, not storage.
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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.