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iostat(1) [bsd man page]

IOSTAT(1)						      General Commands Manual							 IOSTAT(1)

iostat - report I/O statistics SYNOPSIS
iostat [ 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, with priority given to Massbus disk drives (i.e. if both Unibus and Massbus drives are present and the total number of drives exceeds 4, then some number of Unibus drives will not be displayed in favor of the Massbus drives). To force iostat to display specific drives, their names may be supplied on the command line. FILES
/dev/kmem /vmunix SEE ALSO
vmstat(1) 4th Berkeley Distribution April 29, 1985 IOSTAT(1)

Check Out this Related Man Page

iostat(1)						      General Commands Manual							 iostat(1)

       iostat - report I/O statistics

       iostat [ -c ] [ -t ] [ disknames ] [ interval ] [ count ]

       The  command  reports  I/O  statistics for terminals, disks and cpus.  For terminals the number of input and output characters are counted.
       For disks the number of 512 byte blocks per second and number of transfers per second are displayed.  For cpus, it provides the	percentage
       of  time  the system has spent in user mode, in user mode running low priority (niced) processes, in system mode, and idling.  On multipro-
       cessor systems these cpu statistics represent a cumulative summary of all the cpus.

       The optional disknames argument causes disk statistics to be displayed for the specified disks.	If this argument  is  not  specified  then
       disk statistics will be displayed for the first 3 disks only.

       The  optional interval argument causes to report once each interval seconds.  The first report is for all time since a reboot and each sub-
       sequent report is for the last interval only.

       The optional count argument restricts the number of reports.

       -c   Displays the percentage of time each cpu spent in user mode, running low priority (nice'd) processes, in system mode, and idling.

       -t   Displays the number of characters read from and written to terminals.

       This example will cause cpu and disk statistics for the 5 disks ra0, ra1, ra2, ra3, and ra4.
	    iostat ra0 ra1 ra2 ra3 ra4
       This example will cause cpu, terminal, and disk statistics for ra0 to be displayed and updated every 2 seconds.
	    iostat -t ra0 2

See Also
       vmstat(1), cpustat(1)


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