IOSTAT(1M)																IOSTAT(1M)

NAME

       iostat - report I/O statistics

SYNOPSIS

       iostat [ option ] ...  [ interval [ count ] ]

DESCRIPTION

       Iostat  delves into the system and reports certain statistics kept about input-output activity.	Information is kept about up to three dif-
       ferent disks (RF, RK, RP) and about typewriters.  For each disk, IO completions and number of words transferred are counted; for  typewrit-
       ers  collectively, the number of input and output characters are counted.  Also, each sixtieth of a second, the state of each disk is exam-
       ined and a tally is made if the disk is active.	The tally goes into one of four categories, depending on whether the system  is  executing
       in  user  mode, in `nice' (background) user mode, in system mode, or idle.  From all these numbers and from the known transfer rates of the
       devices it is possible to determine information such as the degree of IO overlap and 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.

       With  no  option  argument iostat reports for each disk the number of transfers per minute, the milliseconds per average seek, and the mil-
       liseconds per data transfer exclusive of seek time.  It also gives the percentage of time the system has spend in each of  the  four  cate-
       gories mentioned above.

       The following options are available:

       -t     Report the number of characters of terminal IO per second as well.

       -i     Report  the  percentage  of  time  spend in each of the four categories mentioned above, the percentage of time each disk was active
	      (seeking or transferring), the percentage of time any disk was active, and the percentage of time spent in `IO wait:' idle, but with
	      a disk active.

       -s     Report  the  raw	timing information: 32 numbers indicating the percentage of time spent in each of the possible configurations of 4
	      system states and 8 IO states (3 disks each active or not).

       -b     Report on the usage of IO buffers.

FILES

       /dev/mem, /unix

																	IOSTAT(1M)