Two Effective Actions to Lower CPU Ready Time in vSphere
You manage a vSphere 7 environment with 20 hosts, each with 2 x 10-core CPUs and 512 GB RAM. The environment runs 300 VMs, including a critical ERP application that uses 8 vCPUs and 64 GB RAM. Recently, the ERP VM has been experiencing periodic performance degradation, especially during month-end processing. The host running the ERP VM shows CPU ready time averaging 8%, with spikes to 20% during the processing. The host has 10 other VMs, each with 2-4 vCPUs. The cluster has DRS enabled with default settings. You suspect CPU contention. Which two actions should you take to mitigate the issue? (Choose two.)
Quick Answer
Increasing the CPU shares for the ERP VM is one of the two correct actions because shares determine relative priority when physical cores are actually contended, and the numbers here show real contention, with average ready time at 8% climbing to 20% during month-end processing on a host running ten other VMs alongside the ERP VM. Raising the ERP VM's shares means that whenever the scheduler has to decide which vCPU gets a core first during a busy moment, the ERP VM's requests are weighted more heavily than the other VMs sharing that same host, directly protecting its performance during exactly the periods when contention peaks. This pairs naturally with the complementary fix of reducing the number of VMs competing for cycles on that specific host in the first place, since shares only redistribute priority among VMs that remain on the same host; they do not reduce the total number of vCPUs contending for the physical cores. Together, increasing shares and easing the host's overall VM density attack the problem from both angles: one improves the ERP VM's standing in an already-contended environment, and the other reduces how often that contention occurs. Whenever a scenario describes periodic CPU ready time spikes tied to a predictable high-demand period, and asks for two complementary actions, expect one answer to adjust scheduling priority and the other to address the underlying resource density causing the contention.
⚠ Common exam trap
Test-takers frequently confuse CPU ready time with memory pressure and choose to increase memory or vCPUs, but adding vCPUs actually increases co-scheduling overhead and worsens contention.
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
✓
Migrate the ERP VM to a host with fewer VMs to reduce CPU over-provisioning.
Migrating the ERP VM to a host with fewer VMs reduces the CPU over-provisioning ratio, directly lowering CPU ready time. With 8% average and 20% spikes, the host's physical CPU cores are oversubscribed; moving the VM to a less contended host alleviates the scheduling pressure without changing VM configuration.
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 ERP VM to a host with fewer VMs to reduce CPU over-provisioning.
Why this is correct
Less contention on the target host reduces ready time.
- ✗
Enable DPM and set the cluster to aggressive power management.
Why it's wrong here
DPM consolidates VMs, increasing contention.
- ✓
Increase the CPU shares for the ERP VM to prioritize its scheduling.
Why this is correct
Higher shares ensure the ERP VM gets more CPU time.
- ✗
Increase the number of vCPUs on the ERP VM to 12 to distribute load.
Why it's wrong here
More vCPUs can increase ready time due to co-scheduling.
- ✗
Increase the memory allocation of the ERP VM to reduce ballooning.
Why it's wrong here
Memory does not affect CPU ready time.
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Same concept, more angles
1 more way this is tested on VCP-DCV
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. 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?
easy- A.Migrate the VM to another host with the same CPU load.
- ✓ B.Decrease the number of vCPUs on the VM.
- C.Increase the number of vCPUs on the VM.
- D.Increase the memory reservation for the VM.
Why B: 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.
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.