CV0-004 Troubleshooting Practice Question
A cloud administrator is troubleshooting a web application that is hosted on multiple virtual machines behind a load balancer. Users report that the application is occasionally slow, but the load balancer health checks show all instances as healthy. The administrator suspects that one of the virtual machines is performing poorly. Which of the following should the administrator do to confirm this suspicion?
⚠ Common exam trap
The trap here is assuming that CPU utilization is the definitive indicator of performance, when response time from logs is more directly tied to user experience.
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
✓
Review the load balancer's access logs for response times per backend instance.
Load balancer access logs are a valuable source of per-instance performance data. They record which backend handled each request and how long it took to respond. By examining these logs, the administrator can quickly identify if one instance is consistently slower. This method is non-intrusive and uses existing data, making it the most efficient first step.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Restart each virtual machine one at a time to see if performance improves.
Why it's wrong here
Restarting instances is disruptive and does not confirm which instance is slow. It could temporarily resolve the issue but would not provide diagnostic information. This approach is risky and not recommended for troubleshooting performance issues. It also violates the principle of least disruption in production environments.
- ✓
Review the load balancer's access logs for response times per backend instance.
Why this is correct
Load balancer access logs typically include the backend instance that handled each request and the response time. By analyzing these logs, the administrator can identify if a particular instance has higher response times than others. This is a direct way to confirm which virtual machine is performing poorly without disrupting the service. Other methods may require more invasive actions or may not provide per-instance data.
- ✗
Check the CPU utilization of each virtual machine using the cloud provider's console.
Why it's wrong here
CPU utilization is a useful metric, but a slow instance might be caused by other factors such as memory, disk I/O, or network latency. Without correlating CPU with actual response times, this method may not pinpoint the problematic instance. Access logs provide a more direct measure of user-perceived latency. Therefore, checking CPU alone is insufficient.
- ✗
Enable detailed monitoring on all virtual machines and wait for new metrics.
Why it's wrong here
Enabling detailed monitoring is useful, but it may take time to collect enough data to identify the slow instance. The logs already contain historical data that can be analyzed immediately. Additionally, detailed monitoring might not provide per-request response times as directly as access logs. This option is less efficient for immediate confirmation.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official CompTIA exam blueprint
This CV0-004 practice question is part of Courseiva's free CompTIA 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 CV0-004 exam.