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Table Of Contents
Hosts
The hosts charts contain information about CPU, disk, memory, network, and storage usage for hosts.
The help topic for each chart contains information about the data counters displayed in that chart. The
counters available are determined by the collection level set for vCenter Server.
CPU (%)
The CPU (%) chart displays CPU usage for the host.
This chart is located in the Home view of the Host Performance tab.
Table 144. Data Counters
Chart Label Description
Usage Actively used CPU, as a percentage of the total available CPU, for each physical
CPU on the host.
Active CPU is approximately equal to the ratio of the used CPU to the available CPU.
Available CPU = # of physical CPUs × clock rate.
100% represents all CPUs on the host. For example, if a four-CPU host is running a
virtual machine with two CPUs, and the usage is 50%, the host is using two CPUs
completely.
n
Counter: usage
n
Stats Type: Rate
n
Unit: Percentage (%)
n
Rollup Type: Average (Minimum/Maximum)
n
Collection Level: 1 (4)
Chart Analysis
A short spike in CPU usage indicates that you are making the best use of the host resources. However, if
the value is constantly high, the host is probably lacking the CPU required to meet the demand. A high
CPU usage value can lead to increased ready time and processor queuing of the virtual machines on the
host.
If performance is impacted, consider taking the following actions.
Table 145. CPU Performance Enhancement Advice
# Resolution
1 Verify that VMware Tools is installed on every virtual machine on the host.
2 Set the CPU reservations for all high-priority virtual machines to guarantee that they receive the CPU cycles required.
3 Reduce the number of virtual CPUs on a virtual machine to only the number required to execute the workload. For example, a
single-threaded application on a four-way virtual machine only benefits from a single vCPU. But the hypervisor's maintenance
of the three idle vCPUs takes CPU cycles that could be used for other work.
4 If the host is not already in a DRS cluster, add it to one. If the host is in a DRS cluster, increase the number of hosts and
migrate one or more virtual machines onto the new host.
vSphere Monitoring and Performance
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