System Administration Guide

How to Display Extended Disk Statistics

Run iostat -xtc to get extended disk statistics.

$ iostat -xtc
               extended disk statistics               tty          cpu
disk  r/s w/s Kr/s Kw/s wait actv  svc_t  %w %b  tin tout us sy  wt id
sd0   0.2 1.7  1.0  9.7  0.0  0.1   39.8   0  3   0   9   1  6   9  85
sd1   0.5 2.5 10.6 21.0  0.0  0.1   26.6   0  5      
sd2   0.0 0.2  0.1  0.0  0.0  0.0  157.7   0  0

This command displays a line of output for each disk. The output fields are described in Table 64-5.

Table 64-5 Output From the iostat -xtc Command


Field Name	Description
`r/s`	Reads per second
`w/s`	Writes per second
`Kr/s`	Kbytes read per second
`Kw/s`	Kbytes written per second
`wait`	Average number of transactions waiting for service (queue length)
`actv`	Average number of transactions actively being serviced
`svc_t`	Average service time, in milliseconds
`%w`	Percentage of time the queue is not empty
`%b`	Percentage of time the disk is busy