Two Effective Actions to Lower CPU Ready Time in vSphere
A VM is experiencing high CPU ready time. The host has 16 physical cores and 20 vCPUs total across all VMs. Which action is MOST likely to reduce the CPU ready time on the VM?
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
✓
Decrease the number of vCPUs on the VM.
Reducing the number of vCPUs on an over-provisioned VM decreases scheduling contention, lowering CPU ready time. Increasing vCPUs would worsen the issue. Migrating to another host with similar load would not help long-term. Increasing memory does not directly reduce CPU contention.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Migrate the VM to another host with the same CPU load.
Why it's wrong here
Migrating to a host with the same CPU load leaves the physical-core-to-vCPU oversubscription ratio unchanged, so scheduling delay persists. It is tempting because vMotion is the standard remedy for host contention, and would be correct when the destination host has spare physical cores to relieve the oversubscription.
- ✓
Decrease the number of vCPUs on the VM.
Why this is correct
Fewer vCPUs reduce the number of co-scheduled vCPU worlds competing for the host's 16 physical cores, lowering the scheduler's wait time. CPU ready measures the percentage of time a vCPU is ready but waiting for a physical core, so shrinking the VM's vCPU count directly reduces contention.
- ✗
Increase the number of vCPUs on the VM.
Why it's wrong here
Adding vCPUs increases the count of runnable vCPUs competing for the same 16 physical cores, raising scheduler wait and worsening ready time. It tempts because extra vCPUs help genuinely CPU-bound workloads that are not already contending for host capacity.
- ✗
Increase the memory reservation for the VM.
Why it's wrong here
Memory reservation guarantees RAM allocation and does not alter CPU scheduler wait time; CPU ready reflects vCPUs waiting for physical cores. It is tempting because reservations address resource contention generally, and would be correct when a VM suffers memory ballooning or swapping rather than CPU scheduling delay.
Go deeper
Related to this question
About these practice questions
This VCP-DCV question is part of Courseiva's 281-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
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.