- A
Reduce the number of vCPUs for the database VMs from 16 to 8.
Why wrong: Reducing vCPUs would negatively impact database performance, as the workload benefits from parallel processing.
- B
Disable Hyper-Threading on the new cluster hosts.
Why wrong: Disabling HT would reduce CPU capacity, potentially worsening performance; HT is not the cause of the issue.
- C
Increase the memory reservation for each database VM to prevent ballooning.
Why wrong: Reserving memory prevents ballooning but does not fix NUMA-based performance degradation; it may also waste resources.
- D
Enable vNUMA for the database VMs to align with the physical NUMA topology.
vNUMA allows the guest OS to optimize memory access based on physical NUMA nodes, reducing remote memory access and improving performance.
VCP-DCV vSphere Performance and Scaling Practice Question
This VCP-DCV practice question tests your understanding of vsphere performance and scaling. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company operates a large vSphere environment with 32 ESXi hosts, each featuring 2 sockets, 12 cores per socket (2.6 GHz), and 256 GB RAM. The environment runs a mix of VMs, including several critical database VMs with 16 vCPUs and 128 GB RAM configured. After migrating these database VMs from an older cluster to a new cluster with identical hardware specifications, administrators observe significant performance degradation. vCenter performance charts show high memory ballooning and elevated CPU ready time for these VMs, while overall host utilization remains moderate (CPU 40%, RAM 60%). The new cluster's hosts have two NUMA nodes per socket (each NUMA node spans 6 cores and 64 GB RAM). The older cluster had hosts with a single NUMA node per socket. The administrator confirms that the VMs are running on hosts with sufficient free resources and that no other VMs are contending heavily. What is the most likely cause, and what should the administrator do to resolve the issue?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"most likely"Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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
Enable vNUMA for the database VMs to align with the physical NUMA topology.
The performance degradation is caused by a vCPU-to-NUMA topology mismatch. The database VMs have 16 vCPUs, but each NUMA node in the new cluster has only 6 cores. Without vNUMA enabled, the VM scheduler treats the guest as a single large NUMA domain, causing cross-NUMA memory accesses and high memory ballooning. Enabling vNUMA exposes the physical NUMA topology to the guest OS, allowing it to optimize memory locality and reduce overhead.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Reduce the number of vCPUs for the database VMs from 16 to 8.
Why it's wrong here
Reducing vCPUs would negatively impact database performance, as the workload benefits from parallel processing.
- ✗
Disable Hyper-Threading on the new cluster hosts.
Why it's wrong here
Disabling HT would reduce CPU capacity, potentially worsening performance; HT is not the cause of the issue.
- ✗
Increase the memory reservation for each database VM to prevent ballooning.
Why it's wrong here
Reserving memory prevents ballooning but does not fix NUMA-based performance degradation; it may also waste resources.
- ✓
Enable vNUMA for the database VMs to align with the physical NUMA topology.
Why this is correct
vNUMA allows the guest OS to optimize memory access based on physical NUMA nodes, reducing remote memory access and improving performance.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often attribute performance issues to CPU or memory oversubscription, overlooking the NUMA topology mismatch that occurs when VM vCPU count exceeds a single NUMA node's core count, especially after migrating to hosts with different NUMA configurations.
Detailed technical explanation
How to think about this question
vNUMA (Virtual NUMA) exposes the host's NUMA topology to the guest OS, enabling the guest to make local memory allocations. Without vNUMA, a VM with more vCPUs than a single NUMA node's cores (6 in this case) will span multiple NUMA nodes, causing remote memory accesses that increase latency and trigger ballooning as the hypervisor tries to reclaim memory from remote nodes. This is especially critical for large-memory VMs like databases, where memory locality directly impacts performance.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the VCP-DCV exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
Visual reference
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
- →
vSphere Performance and Scaling — study guide chapter
Learn the concepts, then practise the questions
- →
vSphere Performance and Scaling practice questions
Targeted practice on this topic area only
- →
All VCP-DCV questions
521 questions across all exam domains
- →
VMware Certified Professional Data Center Virtualization VCP-DCV study guide
Full concept coverage aligned to exam objectives
- →
VCP-DCV practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related VCP-DCV practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
vSphere Architecture, Products and Solutions practice questions
Practise VCP-DCV questions linked to vSphere Architecture, Products and Solutions.
Configure and Manage vSphere Networking practice questions
Practise VCP-DCV questions linked to Configure and Manage vSphere Networking.
Configure and Manage vSphere Storage practice questions
Practise VCP-DCV questions linked to Configure and Manage vSphere Storage.
vSphere Lifecycle Management practice questions
Practise VCP-DCV questions linked to vSphere Lifecycle Management.
vSphere Security practice questions
Practise VCP-DCV questions linked to vSphere Security.
vSphere Performance and Scaling practice questions
Practise VCP-DCV questions linked to vSphere Performance and Scaling.
VCP-DCV fundamentals practice questions
Practise VCP-DCV questions linked to VCP-DCV fundamentals.
VCP-DCV scenario practice questions
Practise VCP-DCV questions linked to VCP-DCV scenario.
VCP-DCV troubleshooting practice questions
Practise VCP-DCV questions linked to VCP-DCV troubleshooting.
Practice this exam
Start a free VCP-DCV practice session
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Questions learners often ask
What does this VCP-DCV question test?
vSphere Performance and Scaling — This question tests vSphere Performance and Scaling — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Enable vNUMA for the database VMs to align with the physical NUMA topology. — The performance degradation is caused by a vCPU-to-NUMA topology mismatch. The database VMs have 16 vCPUs, but each NUMA node in the new cluster has only 6 cores. Without vNUMA enabled, the VM scheduler treats the guest as a single large NUMA domain, causing cross-NUMA memory accesses and high memory ballooning. Enabling vNUMA exposes the physical NUMA topology to the guest OS, allowing it to optimize memory locality and reduce overhead.
What should I do if I get this VCP-DCV question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Keep practising
More VCP-DCV practice questions
- A vSphere administrator is managing a cluster with vLCM and receives a notification that a new ESXi patch is available.…
- An administrator needs to apply a security patch to a vLCM-managed cluster. The patch is available as an ESXi image in t…
- An administrator sees the above JSON output from a vLCM compliance report. What should the administrator do to resolve t…
- An administrator is planning to migrate from legacy baselines to vLCM for a cluster. Which TWO statements are true about…
- A vSphere administrator is using vLCM and needs to ensure that all hosts are compliant with the desired image. Which TWO…
- Which TWO actions are recommended to secure the vCenter Server Appliance (VCSA)?
Last reviewed: Jul 4, 2026
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.