6.5.1

Table Of Contents
Fault Tolerance Performance Counters
The fault tolerance charts contain information about CPU and memory for fault tolerant virtual machines.
N The performance charts and help topics for fault tolerance are available only when you have vSphere
Fault Tolerance enabled. If you select a link for a secondary virtual machine in the thumbnail section of the
Resource Pools and Virtual Machines view of the cluster Performance tab, the navigation in the inventory
updates to the primary virtual machine. This occurs because secondary machines are not displayed in the
inventory.
CPU (MHz)
The CPU (MHz) 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 1124. Data Counters
Name Description
Usage The average amount of virtual CPU, per CPU instance, in use on the primary
and secondary fault tolerant virtual machines.
n
Counter: usagemhz
n
Stats Type: Rate
n
Unit: Megaher (MHz)
n
Rollup Type: Average (Minimum/Maximum)
n
Collection Level: 3 (4)
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 1125. CPU Performance Enhancement Advice
# Resolution
1 Verify that the primary and secondary hosts are in the same CPU model family and have similar CPU
congurations. 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 nding the
maximum memory and CPU reservations.
3 Verify that the network and datastore connections for both virtual machines are similar.
4 Turn o 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 insucient CPU resources, potentially making it impossible for the secondary to complete all tasks
completed on a primary in a timely fashion.
5 Turn o 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.
CPU System Time for vCPU (%)
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.
Chapter 1 Monitoring Inventory Objects with Performance Charts
VMware, Inc. 87