VCP-DCV vSphere Performance and Scaling Practice Question
An administrator is troubleshooting a VM that is running slowly. The VM has 4 vCPUs and 16 GB of memory. The host has 2 physical CPUs with 10 cores each, hyper-threading enabled. The administrator runs esxtop and sees that %RDY for the VM is consistently above 15%. Which action would most likely reduce the ready time?
⚠ Common exam trap
It's easy for candidates to assume adding more vCPUs will improve performance, but in reality, over-provisioning vCPUs increases co-scheduling overhead and ready time, making reduction the correct fix.
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
✓
Reduce the number of vCPUs to 2 if the workload does not require 4.
A %RDY value consistently above 15% indicates the VM is ready to run but is waiting for CPU scheduling time on the host. With 4 vCPUs on a host that has 20 logical CPUs (2 sockets × 10 cores × 2 threads), the VM is likely over-provisioned relative to its workload needs, causing co-scheduling contention. Reducing the number of vCPUs to 2 decreases the co-scheduling demands and reduces ready time, as the VM will require fewer physical CPUs to be available simultaneously. Therefore, option D is correct. Increasing CPU shares (option A) would not help if the host is saturated, adding more vCPUs (option B) would worsen contention, and increasing memory (option C) does not address CPU ready time.
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 CPU shares for the VM.
Why it's wrong here
Shares only determine relative entitlement during CPU contention between VMs; they do not reduce ready time when the host has free cores. Raising shares is correct when a competing VM starves this one, but the stem shows no such contention.
- ✗
Increase the number of vCPUs to 8 to improve parallelism.
Why it's wrong here
Adding vCPUs increases the co-scheduling demand placed on the host, raising %RDY further. Extra vCPUs suit genuinely parallel workloads that are CPU-bound but not contended; here the host already has spare physical cores, so the wait reflects scheduling, not insufficient parallelism.
- ✗
Increase the memory allocation to 32 GB.
Why it's wrong here
%RDY measures CPU scheduler wait, so adding memory leaves the contention untouched. Memory sizing addresses ballooning, swapping or overcommitment, and would be the correct action when esxtop shows high swap or memory pressure rather than elevated ready time.
- ✓
Reduce the number of vCPUs to 2 if the workload does not require 4.
Why this is correct
High %RDY means vCPUs wait for physical cores. With hyper-threading, four vCPUs contend for limited logical processors, so reducing to two lowers scheduling pressure and co-stop, directly cutting ready time while still meeting the workload's needs.
Go deeper
Related to this question
About these practice questions
Courseiva writes every VCP-DCV question from scratch — 281 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or 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.