PCDOE Optimizing service performance Practice Question
A company runs a critical application on Compute Engine instances behind a TCP/UDP Network Load Balancer. They notice intermittent high latency for a subset of users. The application logs show no errors, and instance CPU is below 50%. Which next step is most effective to diagnose the latency?
⚠ Common exam trap
It's easy for candidates to assume VPC Flow Logs (Option B) are the go-to tool for diagnosing latency, but they only show flow-level metadata and not latency metrics, whereas Cloud Monitoring provides the specific performance data needed for this scenario.
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
✓
Analyze Cloud Monitoring metrics for the load balancer, including backend latency and request counts.
Cloud Monitoring provides detailed metrics for TCP/UDP Network Load Balancers, including backend latency and request counts, which directly help identify whether the latency originates from the load balancer itself or the backend instances. Since instance CPU is below 50% and application logs show no errors, the issue is likely at the network or load balancer level, and these metrics offer the most targeted diagnostic data without changing the architecture.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Increase the number of instances behind the load balancer.
Why it's wrong here
CPU is low; more instances may not reduce latency.
- ✗
Enable VPC Flow Logs and analyze for dropped packets.
Why it's wrong here
Flow logs show traffic but not latency.
- ✗
Switch to an HTTP(S) Load Balancer for better visibility.
Why it's wrong here
Changing load balancer type is disruptive and may not solve the issue.
- ✓
Analyze Cloud Monitoring metrics for the load balancer, including backend latency and request counts.
Why this is correct
These metrics pinpoint where latency occurs.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This PCDOE practice question is part of Courseiva's free Google Cloud 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 PCDOE exam.