VCP-DCV vSphere Performance and Scaling Practice Question
During a performance review, an administrator notices that a VM with 4 vCPUs and 16 GB memory is experiencing over 10% CPU ready time. The host has two 8-core sockets (hyper-threading enabled) and 256 GB memory. The host runs 15 other VMs with varying CPU loads. What is the most likely cause?
⚠ Common exam trap
It's easy for candidates to confuse CPU ready time with memory-related issues like ballooning or NUMA effects, failing to recognize that CPU ready time is purely a CPU scheduling metric tied to vCPU over-provisioning and physical core availability.
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
✓
Over-provisioning of vCPUs on the host leading to contention.
The host has 16 physical cores (with hyper-threading, 32 logical processors), but running 16 VMs with a total of 4 vCPUs each would require 64 vCPUs. This 2:1 over-provisioning ratio, combined with varying CPU loads, leads to contention for physical CPU resources, manifesting as CPU ready time exceeding 10%. CPU ready time measures the percentage of time a VM is ready to run but waiting for a physical CPU to become available.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
NUMA node mismatch causing cross-node memory access.
Why it's wrong here
NUMA issues cause memory latency, not CPU ready.
- ✗
CPU hot-add is enabled on the VM.
Why it's wrong here
CPU hot-add does not cause high ready time.
- ✗
Memory over-provisioning causing ballooning.
Why it's wrong here
Ballooning affects memory, not CPU ready time.
- ✓
Over-provisioning of vCPUs on the host leading to contention.
Why this is correct
Too many vCPUs relative to cores causes CPU ready time.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This VCP-DCV practice question is part of Courseiva's free VMware 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 VCP-DCV exam.