vCPU

In the Ultra Transcenders books

2V0-18.25

Each book explains vCPU in context, with comparison tables and the common traps.

Terms in this definition

• ESX

  VMware's bare-metal hypervisor, installed on each host in a VCF fleet. Up to version 9.0 it was known as ESXi.

• Physical

  Describes the concrete, real-world parts that put a logical architecture into effect.

• CPU

  The processor that runs a VM's workload (central processing unit); while B-series VMs run under their baseline, they accumulate CPU credits.

Related terms

• Oversized VMs

  vSphere and Hyper-V report that looks at past performance to find VMs with surplus vRAM or vCPU and suggests how much could be taken back. Undersized VMs covers the reverse.

• Prism Central Allocation and Consumption

  Reports how each service was given its resources, the vDisk capacity of every VM, and vCPU and memory trends. It is a tab in the Prism Central Management area.

• property

  In VCF Operations, an attribute describing how an object is configured, such as its vCPU count. Unlike a metric, it captures state rather than performance over time, and it can feed symptom definitions, views, dashboards and reports.

• Virtual machine compatibility

  A VM property that determines which ESX releases the VM is able to run on and what virtual hardware is available to it, for example firmware type, the vCPU limit and memory limit.

• Virtual NUMA

  vSphere feature that exposes a NUMA topology to a VM's guest OS so NUMA-aware operating systems and applications can place threads and memory efficiently. It is enabled by default for VMs with more than eight vCPUs and set at first power-on, changing only if the vCPU count changes.

• %WAIT

  In esxtop's CPU view, this counts time a VM is blocked or busy waiting, idle time included, so a large value alone does not signal trouble. To approximate guest I/O wait, subtract %IDLE from it for the vCPU worlds.