The answer is a single virtual socket with 16 cores, which forces vSphere to create one vNUMA node that spans both physical NUMA nodes, causing cross-node memory access. When a VM’s virtual socket count does not match the host’s physical NUMA node topology—here, two sockets with eight cores each—vSphere cannot align the vNUMA nodes properly, so the single vNUMA node must access memory across the physical NUMA boundary, drastically increasing latency. On the VCP-DCV exam, this scenario tests your understanding of NUMA-aware VM configuration, a common trap where candidates assume more vCPUs simply need more cores per socket, ignoring that vNUMA node count mirrors virtual socket count. The key insight is that for optimal performance, the number of virtual sockets should equal the number of physical NUMA nodes, with cores per socket matching cores per node. Memory tip: “Sockets shape NUMA nodes—match them to avoid cross-node loads.”
VCP-DCV vSphere Performance and Scaling Practice Question
This VCP-DCV practice question tests your understanding of vsphere performance and scaling. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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.
An administrator observes that a VM with 16 vCPUs on a 2-socket host (8 cores per socket, HT disabled) is experiencing poor performance. The VM's NUMA topology shows 2 vNUMA nodes, but performance is worse than expected. What is the most likely reason?
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 the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The VM is configured with a single virtual socket with 16 cores, causing a single vNUMA node that spans both physical NUMA nodes
Option A is correct. If the VM is configured with a single virtual socket (16 cores), vSphere creates one vNUMA node that spans both physical NUMA nodes, causing cross-node memory access. Option B is wrong; insufficient RAM would cause ballooning or swapping. Option C is wrong; memory reservation ensures pages are backed. Option D is wrong; old virtual hardware may limit features but not directly cause this.
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.
✓
The VM is configured with a single virtual socket with 16 cores, causing a single vNUMA node that spans both physical NUMA nodes
Why this is correct
A single vNUMA node across physical NUMA nodes forces cross-node memory access, increasing latency.
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.
✗
The VM's memory is reserved but not backed by physical pages
Why it's wrong here
Memory reservation ensures pages are pre-allocated; this would not degrade performance.
✗
The virtual hardware version is too old
Why it's wrong here
Old virtual hardware might lack some optimizations but is unlikely the primary cause of such a performance drop.
✗
The host has insufficient RAM
Why it's wrong here
Insufficient RAM would cause memory contention, but the issue is specifically poor performance despite expected NUMA topology.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
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.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→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.
What to study next
Got this wrong? Here's your next step.
Identify which VCP-DCV exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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: The VM is configured with a single virtual socket with 16 cores, causing a single vNUMA node that spans both physical NUMA nodes — Option A is correct. If the VM is configured with a single virtual socket (16 cores), vSphere creates one vNUMA node that spans both physical NUMA nodes, causing cross-node memory access. Option B is wrong; insufficient RAM would cause ballooning or swapping. Option C is wrong; memory reservation ensures pages are backed. Option D is wrong; old virtual hardware may limit features but not directly cause this.
What should I do if I get this VCP-DCV question wrong?
Identify which VCP-DCV exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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 →
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. An administrator configures a VM with 4 vCPUs and 32 GB memory on a host with 128 GB RAM and 8 cores (HT enabled). The VM runs a database that requires high memory bandwidth. Performance monitoring shows low CPU usage but high memory latency. Which configuration change is most likely to improve memory performance?
hard
✓ A.Enable the 'Preferred NUMA Node' VM option
B.Increase the memory reservation to 64 GB
C.Disable Hyper-Threading on the host
D.Increase the number of vCPUs to 8
Why A: Option A is correct because Preferred NUMA Node allows the VM to be pinned to a specific NUMA node, reducing cross-node memory access. Option B is wrong; increasing reservation does not improve latency. Option C is wrong; disabling HT reduces overall throughput. Option D is wrong; more vCPUs may increase contention.
Last reviewed: Jun 24, 2026
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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.
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