2V0-620 · Question #81
A virtual machine is experiencing performance issues. The following performance metrics are observed: - CPU usage value for the virtual machine is above 90% - CPU ready value for the virtual machine…
The correct answer is A. Set a CPU reservation for the virtual machine. B. Increase the CPU limit on the virtual machine. High CPU ready time (above 20%) indicates the VM is waiting for CPU cycles, meaning the host is overcommitted. Ensuring the VM has guaranteed and unrestricted CPU access resolves both the usage and scheduling bottleneck.
Question
A virtual machine is experiencing performance issues. The following performance metrics are observed:
- CPU usage value for the virtual machine is above 90%
- CPU ready value for the virtual machine is above 20%
Which two activities will likely resolve the performance issues? (Choose two.)
Options
- ASet a CPU reservation for the virtual machine.
- BIncrease the CPU limit on the virtual machine.
- CDecrease CPU shares equally for all virtual machines on the host.
- DIncrease CPU shares equally for all virtual machines on the host.
How the community answered
(30 responses)- A80% (24)
- C7% (2)
- D13% (4)
Why each option
High CPU ready time (above 20%) indicates the VM is waiting for CPU cycles, meaning the host is overcommitted. Ensuring the VM has guaranteed and unrestricted CPU access resolves both the usage and scheduling bottleneck.
Setting a CPU reservation guarantees a minimum amount of CPU (in MHz) for the VM, ensuring the hypervisor schedules it promptly and directly reduces CPU ready time caused by resource contention.
Increasing the CPU limit removes an artificial cap that may be preventing the VM from consuming available CPU cycles, allowing it to use up to the physical capacity it needs.
Decreasing CPU shares equally for all VMs lowers the relative priority of every VM uniformly, providing no competitive advantage to the struggling VM and potentially worsening its scheduling position.
Increasing CPU shares equally for all VMs maintains the same relative priority ratio between VMs, so the affected VM gains no net benefit over its competitors for CPU time.
Concept tested: vSphere CPU reservation, limit, and ready metric troubleshooting
Source: https://docs.vmware.com/en/VMware-vSphere/7.0/com.vmware.vsphere.resmgmt.doc/GUID-A55FA97A-4F3E-4AA8-A08A-B13C3F97AFD6.html
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