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Performance counters are modeled using the PerfCounterInfo data object type. Each instance of a PerfCounterInfo data object contains metadata about a specific metric available from the system. The disk group of counters support metrics for I/O (input/output) performance (such as latency and read- and write-speeds), and utilization metrics for storage as a finite resource. This page includes documentation for disk I/O performance counters only. See Storage Utilization Counters page for information about storage capacity counters. Disk-I/O counters support metrics for both physical devices and virtual devices:
Some of the counters listed in this table subsume other counters. For example, kernelLatency includes both queueReadLatency and queueWriteLatency. The usage stats include both read and write statistics. |
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| Counter | StatsType | Unit | Level | Per Device Level |
RollupType | Label | Entity | Instance/ Aggregate |
ESX Versions |
|---|---|---|---|---|---|---|---|---|---|
| busResets | delta | number | 2 | 3 | summation | Bus resets | VirtualMachine HostSystem Datastore | instance | 3.5.0 4.0.0 4.1.0 5.0.0 |
| Number of SCSI-bus reset commands issued during the collection interval. | |||||||||
| capacity.contention | absolute | percent | 1 | 2 | average | Storage Capacity Contention | Datastore | aggregate | 3.5.0 4.0.0 4.1.0 5.0.0 |
| The amount of storage capacity overcommitment for the entity, measured in percent. | |||||||||
| capacity.provisioned | absolute | kiloBytes | 3 | 2 | average | Storage Capacity Provisioned | Datastore | aggregate | 3.5.0 4.0.0 4.1.0 5.0.0 |
Provisioned size of the entity:
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| capacity.usage | absolute | kiloBytes | 2 | 3 | average | Storage Capacity Usage | Datastore | instance | 3.5.0 4.0.0 4.1.0 5.0.0 |
| The amount of storage capacity currently being consumed by or on the entity. | |||||||||
| commands | delta | number | 2 | 3 | summation | Commands issued | VirtualMachine HostSystem | instance | 3.5.0 4.0.0 4.1.0 5.0.0 |
| Number of SCSI commands issued during the collection interval. | |||||||||
| commandsAborted | delta | number | 2 | 3 | summation | Commands terminated | VirtualMachine HostSystem Datastore | instance | 3.5.0 4.0.0 4.1.0 5.0.0 |
| Number of SCSI commands aborted during the collection interval. | |||||||||
| commandsAveraged | rate | number | 2 | 3 | average | Average commands issued per second | VirtualMachine HostSystem | instance | 4.1.0 5.0.0 |
| Average number of SCSI commands issued per second during the collection interval. | |||||||||
| deltaused | absolute | kiloBytes | 2 | 3 | latest | Overhead due to delta disk backings | |||
| Storage overhead of a virtual machine or a datastore due to delta disk backings. | |||||||||
| deviceLatency | absolute | millisecond | 1 | 1 | average | Physical device command latency | HostSystem | instance | 3.5.0 4.0.0 4.1.0 5.0.0 |
| Average amount of time, in milliseconds, to complete a SCSI command from the physical device. | |||||||||
| deviceReadLatency | absolute | millisecond | 2 | 3 | average | Physical device read latency | HostSystem | instance | 3.5.0 4.0.0 4.1.0 5.0.0 |
| Average amount of time, in milliseconds, to complete read from the physical device. | |||||||||
| deviceWriteLatency | absolute | millisecond | 2 | 3 | average | Physical device write latency | HostSystem | instance | 3.5.0 4.0.0 4.1.0 5.0.0 |
| Average amount of time, in milliseconds, to write to the physical device (LUN). | |||||||||
| kernelLatency | absolute | millisecond | 2 | 3 | average | Kernel command latency | HostSystem | instance | 3.5.0 4.0.0 4.1.0 5.0.0 |
| Average amount of time, in milliseconds, spent by VMkernel processing each SCSI command. | |||||||||
| kernelReadLatency | absolute | millisecond | 2 | 3 | average | Kernel read latency | HostSystem | instance | 3.5.0 4.0.0 4.1.0 5.0.0 |
| Average amount of time, in milliseconds, spent by VMKernel processing each SCSI read command. | |||||||||
| kernelWriteLatency | absolute | millisecond | 2 | 3 | average | Kernel write latency | HostSystem | instance | 3.5.0 4.0.0 4.1.0 5.0.0 |
| Average amount of time, in milliseconds, spent by VMKernel processing each SCSI write command. | |||||||||
| maxQueueDepth | absolute | number | 1 | 1 | average | Maximum queue depth | HostSystem | instance | 4.1.0 5.0.0 |
| Maximum queue depth. | |||||||||
| maxTotalLatency | absolute | millisecond | 1 | 3 | latest | Highest latency | VirtualMachine HostSystem | aggregate | 4.0.0 4.1.0 5.0.0 |
| Highest latency value across all disks used by the host. Latency measures the time taken to process a SCSI command issued by the guest OS to the virtual machine. The kernel latency is the time VMkernel takes to process an IO request. The device latency is the time it takes the hardware to handle the request. | |||||||||
| numberRead | delta | number | 3 | 3 | summation | Read requests | VirtualMachine HostSystem | instance | 3.5.0 4.0.0 4.1.0 5.0.0 |
Number of disk reads during the collection interval.
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| numberReadAveraged | rate | number | 1 | 1 | average | Average read requests per second | VirtualMachine HostSystem Datastore | instance | 3.5.0 4.0.0 4.1.0 5.0.0 |
| Average number of read commands issued per second to the datastore during the collection interval. | |||||||||
| numberWrite | delta | number | 3 | 3 | summation | Write requests | VirtualMachine HostSystem | instance | 3.5.0 4.0.0 4.1.0 5.0.0 |
Number of disk writes during the collection interval.
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| numberWriteAveraged | rate | number | 1 | 1 | average | Average write requests per second | VirtualMachine HostSystem Datastore | instance | 3.5.0 4.0.0 4.1.0 5.0.0 |
| Average number of write commands issued per second to the datastore during the collection interval. | |||||||||
| queueLatency | absolute | millisecond | 2 | 3 | average | Queue command latency | HostSystem | instance | 3.5.0 4.0.0 4.1.0 5.0.0 |
| Average amount of time spent in the VMkernel queue, per SCSI command, during the collection interval. | |||||||||
| queueReadLatency | absolute | millisecond | 2 | 3 | average | Queue read latency | HostSystem | instance | 3.5.0 4.0.0 4.1.0 5.0.0 |
| Average amount of time taken during the collection interval per SCSI read command in the VMKernel queue. | |||||||||
| queueWriteLatency | absolute | millisecond | 2 | 3 | average | Queue write latency | HostSystem | instance | 3.5.0 4.0.0 4.1.0 5.0.0 |
| Average amount time taken during the collection interval per SCSI write command in the VMKernel queue. | |||||||||
| read | rate | kiloBytesPerSecond | 2 | 3 | average | Read rate | VirtualMachine HostSystem Datastore | instance | 3.5.0 4.0.0 4.1.0 5.0.0 |
Average number of kilobytes read from the disk each second during the collection interval.
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| scsiReservationCnflctsPct | absolute | percent | 2 | 4 | average | Disk SCSI Reservation Conflicts % | |||
| Number of SCSI reservation conflicts as a percent of total commands for the virtual disk during the collection interval. | |||||||||
| scsiReservationConflicts | delta | number | 2 | 2 | summation | Disk SCSI Reservation Conflicts | |||
| Number of SCSI reservation conflicts for the virtual disk during the collection interval. | |||||||||
| throughput.contention | absolute | millisecond | 3 | 1 | average | Disk Throughput Contention | ResourcePool | aggregate | 3.5.0 4.0.0 4.1.0 5.0.0 |
| Average amount of time for an I/O operation to complete. | |||||||||
| throughput.usage | rate | kiloBytesPerSecond | 3 | 1 | average | Disk Throughput Usage | ResourcePool | aggregate | 3.5.0 4.0.0 4.1.0 5.0.0 |
| Aggregated disk I/O rate. For hosts, this metric includes the rates for all virtual machines running on the host during the collection interval. | |||||||||
| totalLatency | absolute | millisecond | 3 | 3 | average | Command latency | HostSystemDatastore | instance | 3.5.0 4.0.0 4.1.0 5.0.0 |
| Average amount of time taken during the collection interval to process a SCSI command issued by the Guest OS to the virtual machine. The sum of kernelLatency and deviceLatency. | |||||||||
| totalReadLatency | absolute | millisecond | 2 | 3 | average | Read latency | HostSystem | instance | 3.5.0 4.0.0 4.1.0 5.0.0 |
| Average amount of time taken during the collection interval to process a SCSI read command issued from the Guest OS to the virtual machine. The sum of kernelReadLatency and deviceReadLatency. | |||||||||
| totalWriteLatency | absolute | millisecond | 2 | 3 | average | Write latency | HostSystem | instance | 3.5.0 4.0.0 4.1.0 5.0.0 |
| Average amount of time taken during the collection interval to process a SCSI write command issued by the Guest OS to the virtual machine. The sum of kernelWriteLatency and deviceWriteLatency. | |||||||||
| usage | rate | kiloBytesPerSecond | 1 (4) | 4 | average (minimum) (maximum) (none) | Usage | VirtualMachine HostSystem | aggregate | |
| Aggregated disk I/O rate. For hosts, this metric includes the rates for all virtual machines running on the host during the collection interval. | |||||||||
| write | rate | kiloBytesPerSecond | 1 | 3 | average | Write rate | VirtualMachine HostSystem Datastore | instance | 3.5.0 4.0.0 4.1.0 5.0.0 |
Average number of kilobytes written to disk each second during the collection interval.
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