vRealize Operations Manager collects CPU use, disk, memory, network, and summary metrics for objects in the vSphere world.

Capacity metrics can be calculated for vSphere world objects. See Capacity and Project-Based Metrics.

CPU Usage Metrics

CPU usage metrics provide information about CPU use.

Table 1. CPU Usage Metrics

Metric Name


CPU|Capacity usage

CPU usages as a percent during the interval.

Key: cpu|capacity_usagepct_average

CPU|CPU contention(%)

This metric shows the percentage of time the VMs in the ESXi hosts are unable to run because they are contending for access to the physical CPUs. The number shown is the average number for all VMs. The number will be lower than the highest number experienced by the VM that is most impacted by CPU contention.

Use this metric to verify if the host can serve all its VMs efficiently. Low contention means that the VM can access everything it demands to run smoothly. It means that the infrastructure is providing good service to the application team.

When using this metric, ensure that the number is within your expectation. Look at both the relative number and the absolute number. Relative means a drastic change in value, meaning that the ESXi is unable to serve the VMs. Absolute means that the real value itself is high. Investigate why the number is high. One factor that impacts this metric is CPU Power Management. If CPU Power Management clocks down the CPU speed from 3 GHz to 2 GHz, the reduction in speed is accounted for because it shows that the VM is not running at full speed.

This metric is calculated in the following way: cpu|capacity_contention / (200 * summary|number_running_vcpus)

Key: cpu|capacity_contentionPct

CPU|Demand (%)

This metric shows the amount of CPU resources a virtual machine would use if there were no CPU contention or CPU limit. This metric represents the average active CPU load for the past five minutes.

Keep this number below 100% if you set the power management to maximum.

This metric is calculated in the following way: ( cpu.demandmhz / cpu.capacity_provisioned)*100

Key: cpu|demandPct

CPU|Demand (MHz)

This metric shows the amount of CPU resources a virtual machine would use if there were no CPU contention or CPU limit.

Key: cpu|demandmhz


CPU demand in megahertz.

Key: cpu|demand_average

CPU|IO wait

IO wait (ms).

Key: cpu|iowait

CPU|number of CPU Sockets

Number of CPU sockets.

Key: cpu|numpackages

CPU|Overall CPU Contention

Overall CPU contention in milliseconds.

Key: cpu|capacity_contention

CPU|Provisioned Capacity (MHz)

capacity in MHz of the physical CPU cores.

Key: cpu|capacity_provisioned

CPU|Provisioned vCPU(s)

Number of provisioned CPU cores.

Key: cpu|corecount_provisioned

CPU|Reserved Capacity (MHz)

Total CPU capacity reserved by virtual machines.

Key: cpu|reservedCapacity_average

CPU|Usage (MHz)

CPU usages, as measured in megahertz, during the interval.

  • VM - Amount of actively used virtual CPU. This is the host's view of the CPU usage, not the guest operating system view.

  • Host - Sum of the actively used CPU of all powered on virtual machines on a host. The maximum possible value is the frequency of the two processors multiplied by the number of processors. For example, if you have a host with four 2 GHz CPUs running a virtual machine that is using 4000 MHz, the host is using two CPUs completely: 400 / (4 2000) = 0.50

Key: cpu|usagemhz_average


Total CPU time spent in wait state. The wait total includes time spent in the CPU Idle, CPU Swap Wait, and CPU I/O Wait states.


CPU|Workload (%)

Percent of workload

Key: cpu|workload

Memory Metrics

Memory metrics provide information about memory use and allocation.

Table 2. Memory Metrics

Metric Name


mem|Contention (%)

This metric shows the percentage of time VMs are waiting to access swapped memory.

Use this metric to monitor ESXi memory swapping. A high value indicates that the ESXi is running low on memory, and a large amount of memory is being swapped.

Key: mem|host_contentionPct

mem|Machine Demand (KB)

Host memory demand in kilobytes.

Key: mem|host_demand

mem|Provisioned Memory

Provisioned host memory in kilobytes.

Key: mem|host_provisioned

mem|Reserved Capacity (KB)

Total amount of memory reservation used by powered-on virtual machines and vSphere services on the host.

Key: mem|reservedCapacity_average

mem|Usable Memory (KB)

Usable host memory in kilobytes.

Key: mem|host_usable

mem|Host Usage (KB)

Host memory use in kilobytes.

Key: mem|host_usage

mem|Usage/Usable (%)

Memory usage as percentage of total configured or available memory.

Key: mem|host_usagePct

mem|Workload (%)

Percent of workload.

Key: mem|workload

Network Metrics

Network metrics provide information about network performance.

Table 3. Network Metrics

Metric Name


net|Packets Dropped (%)

This metric shoes the percentage of received and transmitted packets dropped in the collection interval.

Use this metric to monitor the reliability and performance of the ESXi network. A high value indicates that the network is not reliable and performance decreases.

Key: net|droppedPct

net|Usage Rate (KB per second)

Sum of the data transmitted and received for all of the NIC instances of the host or virtual machine.

Key: net|usage_average

net|Workload (%)

Percent of workload.

Key: net|workload

Disk Metrics

Disk metrics provide information about disk use.

Table 4. Disk Metrics

Metric Name


disk|Commands per second

Average number of commands issued per second during the collection cycle.

Key: disk|commandsAveraged_average

disk|Usage Rate (KB per second)

Average of the sum of the data read and written for all of the disk instances of the host or virtual machine.

Key: disk|usage_average

disk|Workload (%)

Percent of workload.

Key: disk|workload

Summary Metrics

Summary metrics provide information about overall performance.

Table 5. Summary Metrics

Metric Name


summary|Number of Running Hosts

Number of running hosts.

Key: summary|number_running_hosts

summary|Number of Running VMs

This metric shows the number of running VMs at a given point in time. The data is sampled every five minutes.

A large number of running VMs might be a reason for CPU or memory spikes because more resources are used in the host. The number of running VMs gives you a good indicator of how many requests the ESXi host must juggle. Powered off VMs are not included because they do not impact ESXi performance. A change in the number of running VMs can contribute to performance problems. A high number of running VMs in a host also means a higher concentration risk, because all the VMs will fail if the ESXi crashes.

Use this metric to look for a correlation between spikes in the running VMs and spikes in other metrics such as CPU contention, or memory contention.

Key: summary|number_running_vms

summary|Total Number of Clusters

Total number of clusters.

Key: summary|total_number_clusters

summary|Total Number of Datastores

Total number of datastores.

Key: summary|total_number_datastores

summary|Total Number of Hosts

Total number of hosts.

Key: summary|total_number_hosts

summary|Total Number of VMs

Total number of virtual machines.

Key: summary|total_number_vms

summary|Total Number of Datacenters

Total number of data centers.

Key: summary|total_number_datacenters

summary|Number VCPUs on Powered on VMs

Number of virtual CPUs on powered-on virtual machines.

Key: summary|number_running_vcpus

summary|Average Running VM Count per Running Host

Average running virtual machine count per running host.

Key: summary|avg_vm_density