- A
Use a vSphere DRS rule to disable hyperthreading for all VMs in the cluster, avoiding the need to modify host BIOS.
Why wrong: vSphere does not have a DRS rule to disable hyperthreading; it is a BIOS-level setting.
- B
Place each host in maintenance mode individually, disable hyperthreading in the host BIOS, reboot the host, and then move to the next host. Rebalance VMs after all hosts are updated.
This minimizes downtime as VMs are migrated off each host before reboot, and can be completed within 48 hours.
- C
Delay the change and schedule a maintenance window for the next month when business impact is lower.
Why wrong: This does not meet the 48-hour requirement.
- D
Disable hyperthreading on all hosts simultaneously using a vSphere Cluster feature, then reboot all hosts at once during off-peak hours.
Why wrong: Rebooting all hosts at once would cause significant downtime and is not feasible within the 48-hour window.
Quick Answer
The correct answer is to place each host in maintenance mode individually, disable hyperthreading in the host BIOS, reboot, and then move to the next host, rebalancing VMs after all hosts are updated. This is the only supported method because mitigating side-channel attacks like L1TF or MDS requires a permanent BIOS-level change, which cannot be applied dynamically through software settings in vSphere 7.0. By using vMotion to migrate VMs off each host before the reboot, the administrator avoids simultaneous downtime and meets the 48-hour deadline without disrupting business hours, even with mixed CPU-intensive and memory-bound workloads. On the VCP-DCV exam, this scenario tests your understanding that hyperthreading is a hardware feature controlled at the BIOS level, not a cluster setting—a common trap is assuming you can disable it via host profiles or a rolling reboot without maintenance mode. Remember the mnemonic: “BIOS before boot, vMotion to stay afloat.”
VCP-DCV vSphere Security Practice Question
This VCP-DCV practice question tests your understanding of vsphere security. 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 large financial institution runs a vSphere 7.0 environment with 100 ESXi hosts and 2,000 VMs. The security team has identified that several VMs are vulnerable to a critical side-channel attack that requires disabling hyperthreading on the ESXi hosts. The administrator needs to implement a solution that minimizes performance impact while ensuring compliance. The environment uses DRS clusters with varying workloads: some VMs are CPU-intensive (financial modeling) and others are memory-bound (database servers). The administrator cannot afford to take hosts offline for maintenance during business hours. The change must be implemented within 48 hours. Which course of action should the administrator take?
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
Place each host in maintenance mode individually, disable hyperthreading in the host BIOS, reboot the host, and then move to the next host. Rebalance VMs after all hosts are updated.
Option B is correct because disabling hyperthreading to mitigate side-channel attacks (e.g., L1TF or MDS) requires a host BIOS change, which necessitates a reboot. The only supported method in vSphere 7.0 is to place each host into maintenance mode, change the BIOS setting, reboot, and then repeat for all hosts. This approach minimizes performance impact by allowing VMs to be migrated via vMotion and avoids simultaneous downtime, meeting the 48-hour requirement without taking all hosts offline during business hours.
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.
- ✗
Use a vSphere DRS rule to disable hyperthreading for all VMs in the cluster, avoiding the need to modify host BIOS.
Why it's wrong here
vSphere does not have a DRS rule to disable hyperthreading; it is a BIOS-level setting.
- ✓
Place each host in maintenance mode individually, disable hyperthreading in the host BIOS, reboot the host, and then move to the next host. Rebalance VMs after all hosts are updated.
Why this is correct
This minimizes downtime as VMs are migrated off each host before reboot, and can be completed within 48 hours.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Delay the change and schedule a maintenance window for the next month when business impact is lower.
Why it's wrong here
This does not meet the 48-hour requirement.
- ✗
Disable hyperthreading on all hosts simultaneously using a vSphere Cluster feature, then reboot all hosts at once during off-peak hours.
Why it's wrong here
Rebooting all hosts at once would cause significant downtime and is not feasible within the 48-hour window.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates mistakenly believe hyperthreading can be disabled via a vSphere software setting (like a DRS rule or cluster feature) without a host reboot, when in reality it requires a physical BIOS change and reboot per host.
Detailed technical explanation
How to think about this question
Hyperthreading (Intel Hyper-Threading Technology) exposes logical processors that share physical cores, enabling side-channel attacks like L1 Terminal Fault (L1TF) and Microarchitectural Data Sampling (MDS). In vSphere 7.0, the hyperthreading state is read from the host BIOS and exposed as a CPU feature; vSphere cannot programmatically change it without a reboot. When hyperthreading is disabled in BIOS, the ESXi host sees only physical cores, reducing CPU capacity but eliminating the shared-resource vulnerability. In mixed-workload clusters, disabling hyperthreading disproportionately impacts CPU-intensive VMs (e.g., financial modeling) because they lose logical processor throughput, while memory-bound VMs (e.g., databases) are less affected, so careful DRS rebalancing after the change is critical.
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.
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.
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vSphere Security — study guide chapter
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FAQ
Questions learners often ask
What does this VCP-DCV question test?
vSphere Security — This question tests vSphere Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Place each host in maintenance mode individually, disable hyperthreading in the host BIOS, reboot the host, and then move to the next host. Rebalance VMs after all hosts are updated. — Option B is correct because disabling hyperthreading to mitigate side-channel attacks (e.g., L1TF or MDS) requires a host BIOS change, which necessitates a reboot. The only supported method in vSphere 7.0 is to place each host into maintenance mode, change the BIOS setting, reboot, and then repeat for all hosts. This approach minimizes performance impact by allowing VMs to be migrated via vMotion and avoids simultaneous downtime, meeting the 48-hour requirement without taking all hosts offline during business hours.
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.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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Last reviewed: Jun 11, 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.
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