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NAME    [Toc]    [Back]

       iostat - Reports I/O statistics

SYNOPSIS    [Toc]    [Back]

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

OPERANDS    [Toc]    [Back]

       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).   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.  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    [Toc]    [Back]

       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    [Toc]    [Back]

       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    [Toc]    [Back]

       Commands:  vmstat(1)

[ Back ]
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