iostat(1)
NAME
iostat − report I/O statistics
SYNOPSIS
iostat [−t] [interval [count]]
DESCRIPTION
iostat iteratively reports I/O statistics for each active disk on the system. Disk data is arranged in a three-column format:
Column Heading
Interpretation
bps Kilobytes transferred per second
sps Number of seeks per second
msps Milliseconds per average seek
If two or more disks are present, data for successive disks is presented side-by-side across the page.
To compute this information, seeks, data transfer completions, and the number of words transferred are counted for each disk. Also, the state of each disk is examined HZ times per second (as defined in <sys/param.h>) and a tally is made if the disk is active. These numbers can be combined with the transfer rates of each device to determine average seek times for each device.
Options
The following options are recognized:
−t Report terminal statistics as well as disk statistics. Terminal statistics include:
tin Number of characters read from terminals.
tout Number of characters written to terminals.
us Percentage of time system has spent in user mode.
ni Percentage of time system has spent in user mode running low-priority (niced) processes.
sy Percentage of time system has spent in system mode.
id Percentage of time system has spent idling.
interval Display successive lines which are summaries over the last interval seconds. The first line reported is for the time since a reboot and each subsequent line is for the last interval only.
count Repeat the statistics count times.
EXAMPLES
Show current I/O statistics for all disks:
iostat
Display I/O statistics for all disks every 10 seconds until INTERRUPT or QUIT is pressed:
iostat 10
Display I/O statistics for all disks every 10 seconds and terminate after 5 successive readings:
iostat 10 5
Same except also show terminal and processor statistics:
iostat −t 10 5
DEPENDENCIES
Series 300/400
iostat does not yet report disk information for SCSI disks.
AUTHOR
iostat was developed by the University of California, Berkeley, and HP.
SEE ALSO
Hewlett-Packard Company — HP-UX Release 8.05: June 1991