The CPU System Time chart displays virtual CPU usage for fault tolerant virtual machines.

This chart is located in the Fault Tolerance view of the Virtual Machine Peformance tab. It is available only at collection levels 3 and 4.

Table 1. Data Counters
Chart Label Description
System Amount of time spent on system processes on each virtual CPU in the virtual machine.
Note: This is the host view of the CPU usage, not the guest operating system view.
  • Counter: system
  • Stats Type: Delta
  • Unit: Percentage (%)
  • Rollup Type: Summation
  • Collection Level: 3

Chart Analysis

A large discrepancy in CPU usage between the primary and secondary virtual machines might indicate performance problems. The CPU ready, system, and wait times of each virtual machine should be synchronized. A large discrepancy in these values might indicate performance problems. Consider taking the following actions.

Table 2. CPU Performance Enhancement Advice
# Resolution
1 Verify that the primary and secondary hosts are in the same CPU model family and have similar CPU configurations. For best results, use CPUs with the same stepping level.
2 Verify that the CPU resource reservations set for both virtual machines are consistent within the cluster. VMware HA plans for a worst-case scenario by considering all powered on virtual machines in a cluster and finding the maximum memory and CPU reservations.
3 Verify that the network and datastore connections for both virtual machines are similar.
4 Turn off power management (also known as power-capping) in the BIOS. If power management is enabled, the secondary host might enter lower performance, power-saving modes. Such modes can leave the secondary virtual machine with insufficient CPU resources, potentially making it impossible for the secondary to complete all tasks completed on a primary in a timely fashion.
5 Turn off hyperthreading in the BIOS. If hyperthreading is enabled and the secondary virtual machine is sharing a CPU with another demanding virtual machine, the secondary virtual machine might run too slowly to complete all tasks completed on the primary in a timely fashion.