# Counters for Disk Performance

This table contains the values for each category of the counters that measure Disk performance.

### GROUP NAME: disk

Counter Name | Category | Value
--- | --- | ---
usage
unit | KBps
description | Collected storage performance statistics for the managed entity.
statistic type | rate
rollup type | all
entity | host, virtual machine (aggregate level only)
numberRead
unit | number
description | Number of times data was read from the disk in the defined interval.
statistic type | delta
rollup type | summation
entity | host, virtual machine (device instance only)
numberWrite
unit | number
description | Number of times data was written to the disk in the defined interval.
statistic type | delta
rollup type | summation
entity | host, virtual machine (device instance only)
read
unit | KBps
description | Amount of data read in the defined interval.
statistic type | rate
rollup type | all
entity | host, virtual machine (device instance only)
write
unit | KBps
description | Amount of data written to disk during the defined interval.
statistic type | rate
rollup type | all
entity | host, virtual machine (device instance only)