IOSTAT(1)IOSTAT(1)NAMEiostat - report I/O statistics
SYNOPSISiostat [ drives ] [ interval [ count ] ]
DESCRIPTION
Iostat iteratively reports the number of characters read and written to
terminals per second, and, for each disk, the number of transfers per
second, kilobytes transferred per second, and the milliseconds per
average seek. It also gives the percentage of time the system has
spent in user mode, in user mode running low priority (niced)
processes, in system mode, and idling.
To compute this information, for each disk, seeks and data transfer
completions and number of words transferred are counted; for terminals
collectively, the number of input and output characters are counted.
Also, each sixtieth of a second, the state of each disk is examined and
a tally is made if the disk is active. From these numbers and given
the transfer rates of the devices it is possible to determine average
seek times for each device.
The optional interval argument causes iostat to report once each
interval seconds. The first report is for all time since a reboot and
each subsequent report is for the last interval only.
The optional count argument restricts the number of reports.
If more than 4 disk drives are configured in the system, iostat
displays only the first 4 drives. To force iostat to display specific
drives, their names may be supplied on the command line.
FILES
/dev/kmem
/mach
SEE ALSOvm_stat(1)4th Berkeley Distribution April 29, 1985 IOSTAT(1)