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iostat(1)


NAME

  iostat - Reports I/O statistics


SYNOPSIS

  iostat [drive...] [interval] [count]


OPERANDS

  drive...
      Forces iostat to display specific drives.	 If drive is not specified
      (or the specified drive does not exist on the system or cluster, iostat
      displays the first two drives (even if more than two disk drives are
      configured in the system).

  interval
      Causes iostat to report once each interval seconds.  The first report
      is for all time since the system was last booted, and each subsequent
      report is for the last interval only.The value must not be 0.

  count
      Specifies the number of reports.	For example, iostat 1 10 would
      produce 10 reports at 1-second intervals.	 You cannot specify count
      without interval because the first numeric argument to iostat is
      assumed to be interval.


DESCRIPTION

  The iostat command reports the following information:

    ·  For terminals (collectively), the number of characters read and
       written per second.

    ·  For each disk, the number of transfers per second and bytes
       transferred per second (in kilobytes).

    ·  For the system, the percentage of time the system has spent in user
       mode, in user mode running low priority (nice) processes, in system
       mode, and idling.

  To compute this information, iostat counts data transfer completions, the
  number of words transferred for each disk, and the collective number of
  input and output characters for terminals. Also, each sixtieth of a second,
  iostat examines the state of each disk and makes a tally if the disk is
  active.

  When you issue an iostat command on a cluster member, it displays
  statistics only for those disks that are local to the member and that
  member's usage of those shared disks that it has mounted.   It displays 0
  for other disks in the cluster (those it doesn't have mounted), regardless
  of whether they are on the shared bus or are local to some other member.


EXAMPLES

  The output from this example displays cpu, terminal, and disk statistics
  for the first two disks on the system providing 5 reports at 1 second
  intervals:

       # iostat 1 5
	   tty	    floppy1	     dsk9	   cpu
	tin tout    bps	   tps	  bps	 tps  us ni sy id
	  0    3      0	     0	    0	   0   1  0  4 95
	  4   58      0	     0	    0	   0   1  0  2 97
	  1   53      0	     0	    0	   0   0  0  2 98
	  5   59      0	     0	    0	   0   1  0  1 98
	  6   60      0	     0	    0	   0   1  0  2 97

  The second example specifies device names in the command:

       # iostat dsk2 dsk3 cdrom2
	      tty	dsk2	cdrom2	     dsk3	  cpu
	tin   tout  bps	 tps  bps  tps	 bps  tps  us  ni  sy  id
	  0    13    11	  5    5    2	2427 1213   0	1   1  98


SEE ALSO

  Commands:vmstat(1)

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