VCP-DCV vSphere Performance and Scaling Practice Test 3 — 15 Questions

Question 1

An administrator has a vSphere 7 cluster with vMotion enabled. They need to perform a vMotion of a VM from host1 to host2 while preserving the VM's memory state. The VM has a PCIe passthrough device assigned (NVMe controller). What should the administrator do before initiating the vMotion?

Accepted Answer

Remove the PCIe passthrough device from the VM. vMotion does not support VMs with PCIe passthrough devices because the device is tied to the physical host. The device must be removed or the VM must be powered off.

Answer

Use shared storage for the VM

Answer

Enable Enhanced vMotion Compatibility (EVC) on the cluster

Answer

Upgrade to vSphere 8

Question 2

A vSphere environment experiences periodic performance degradation during peak business hours. Analysis shows that one ESXi host's CPU ready time for a specific mission-critical VM is consistently above 20%. Which corrective action should be taken first?

Accepted Answer

Migrate the VM to a different host with lower CPU utilization. High ready time indicates CPU contention. Moving the VM to a less loaded host using DRS or manual migration can immediately reduce ready time. Increasing resources without addressing contention is ineffective.

Answer

Increase the VM's memory reservation

Answer

Set a higher CPU limit on the VM

Answer

Add more vCPUs to the VM

Question 3

Which tool provides real-time performance monitoring at the ESXi host level, including CPU, memory, network, and storage metrics?

Accepted Answer

esxtop. esxtop is a command-line tool that provides real-time host performance data. vCenter performance charts are historical. resxtop is for remote usage, and dcli is a different tool.

Answer

dcli

Answer

resxtop

Answer

vCenter performance charts

Question 4

A vSAN stretched cluster is configured with two witness hosts to allow for site failures. Performance troubleshooting reveals that write latency for synchronous writes is higher than expected for cross-site operations. Which setting should be reviewed as a likely cause?

Accepted Answer

vSAN preferred fault domain configuration. In a stretched cluster, if the network latency between sites is high, it can increase write latency. The preferred fault domain setting can also affect latency if the VM's data is not local.

Answer

vSAN deduplication and compression

Answer

vSAN object repair timer

Answer

vSAN network MTU setting

Question 5

An administrator is planning to scale a vSphere cluster from 8 to 16 hosts. Which consideration is most important for maintaining vSphere HA effectiveness?

Accepted Answer

Increase the number of heartbeat datastores per host. As cluster size increases, the number of heartbeat datastores must be sufficient to ensure isolation detection. Admission control policy and slot size also matter but heartbeat datastores are critical for scaling.

Answer

Assign multiple master hosts to the cluster

Answer

Disable admission control to reduce complexity

Answer

Adjust the slot size for admission control

Question 6

A VM configured with 4 vCPUs shows high co-stop time in performance metrics. What does co-stop time indicate and which action should be taken to improve performance?

Accepted Answer

Reduce the number of vCPUs to match workload requirements. Co-stop time is time when the VM is ready to run but waiting for all vCPUs to be scheduled simultaneously. Reducing the number of vCPUs can alleviate this.

Answer

Add more vCPUs to the VM

Answer

Enable hyperthreading on the host

Answer

Increase the VM's memory reservation

Question 7

In a vSphere 8 environment with vGPU vMotion enabled, an administrator attempts a vMotion of a VM that has a NVIDIA vGPU profile assigned. The vMotion fails with an error. What is the most likely cause?

Accepted Answer

The VM's virtual hardware version is not supported for vGPU vMotion. vGPU vMotion has specific requirements; the VM must use virtual hardware version 19 or later. If the VM uses an older version, vMotion will fail.

Answer

Insufficient network bandwidth between the hosts

Answer

The destination host has a different GPU model

Answer

The vGPU license is not assigned to the VM

Question 8

Which TWO actions can be taken to reduce CPU ready time for a virtual machine? (Select TWO.)

Accepted Answer

Decrease the number of vCPUs to match the workload. Option B is correct because reducing the number of vCPUs to match the actual workload demand directly decreases the co-scheduling overhead and contention for physical CPU cores. When a VM has more vCPUs than its workload requires, the ESXi scheduler must wait for all assigned vCPUs to become available simultaneously, which inflates CPU ready time. Right-sizing vCPUs to the workload is a best practice to minimize ready time and improve performance.

Answer

Enable CPU hot-add and hot-plug for the VM

Answer

Migrate the VM to a host with more physical CPU cores

Answer

Add more vCPUs to the VM

Question 9

Which THREE vSphere features directly contribute to performance and scaling of virtualized workloads? (Select THREE.)

Accepted Answer

vSphere vMotion. DRS balances load, SIOC manages storage I/O, and vMotion enables migration for scaling and maintenance. HA provides availability, FT provides fault tolerance, and Backup does not scale performance.

Answer

vSphere Fault Tolerance

Answer

vSphere HA

Question 10

Which TWO conditions are required for a successful vMotion of a powered-on virtual machine? (Select TWO.)

Accepted Answer

The VM must have its virtual disks on shared storage accessible to both hosts. Shared storage for the VM's disks and compatible CPUs are required. Identical network is not necessary; the VM can be reconnected. Same vCenter is not required for cross vCenter vMotion.

Answer

The source and destination hosts must have identical physical network adapters

Answer

Both hosts must be managed by the same vCenter Server

Answer

The VM must be connected to the same VLAN on both hosts

Question 11

Refer to the exhibit. The vSphere administrator observes that vm1 has a %RDY value of 20.5. What is the most likely cause of this high ready time?

Accepted Answer

The host's physical CPUs are overcommitted. High %RDY indicates the VM is ready to run but is being queued due to CPU contention. This is typically caused by overcommitment of pCPUs. Memory or storage latency would show in other counters.

Answer

The VM is experiencing network packet loss

Answer

The VM's virtual disk is causing I/O latency

Answer

Insufficient memory is allocated to vm1

Question 12

Refer to the exhibit. An administrator sees two DRS recommendations. Which action should the administrator take first to reduce cluster imbalance?

Accepted Answer

Migrate DB01 to host04 first. The DB01 migration provides a higher benefit (15%) compared to Web01 (10%). Starting with the higher impact migration reduces imbalance more effectively.

Answer

Migrate Web01 to host04 first

Answer

Migrate both VMs simultaneously

Answer

Ignore the recommendations; the cluster is balanced

Question 13

Refer to the exhibit. The administrator is troubleshooting performance for VM 'vm2'. Based on the log, what is the performance issue?

Accepted Answer

The VM is not experiencing significant CPU performance issues. The CPU ready time values (around 3%) are within acceptable thresholds (typically under 5%). There is no indication of contention or overcommitment.

Answer

The host is overloaded with too many VMs

Answer

The VM is experiencing high CPU ready time indicating starvation

Answer

The VM has a memory balloon driver issue

Question 14

An administrator notices that a critical virtual machine is running slowly. The VM has 8 vCPUs and 32GB memory. The host is an ESXi 7.0 server with two Intel Xeon Gold 6248 sockets (20 cores each, hyperthreading enabled). The VM's CPU ready time is consistently above 10%. What is the most likely cause?

Accepted Answer

The host has too many VMs running and CPU oversubscription is too high.. High CPU ready time indicates the VM is ready to run but the hypervisor cannot schedule it. This is typically due to excessive CPU oversubscription. Option A is incorrect because 8 vCPUs is not over-provisioned relative to 80 logical CPUs. Option B is incorrect as NUMA pinning generally affects memory locality, not ready time. Option D is incorrect because disk I/O does not cause CPU ready time.

Answer

The VM's vCPUs are pinned to a single NUMA node causing contention.

Answer

The VM is over-provisioned on vCPUs relative to the host's physical cores.

Answer

The VM is using Eager Zero Thick disks causing high I/O latency.

Question 15

A company uses vSphere 7 with Distributed Resource Scheduler (DRS). They want to ensure that VMs are migrated to hosts with more available resources during peak load. Which default DRS setting controls the aggressiveness of initial placement and migration?

Accepted Answer

Migration threshold. The DRS migration threshold (1-5) determines how aggressively DRS will recommend and apply migrations. Option A is correct. Options B, C, D are unrelated to DRS migration aggressiveness.

Answer

VM monitoring sensitivity

Answer

EVC mode

Answer

HA admission control