NAME    [Toc]    [Back]

     iostat - report I/O statistics

SYNOPSIS    [Toc]    [Back]

     iostat [-CdDIT] [-c count] [-M core] [-N system]  [-w  wait]
[drives]

DESCRIPTION    [Toc]    [Back]

     iostat  displays kernel I/O statistics on terminal, disk and
CPU operations.
  By default, iostat displays one line  of  statistics
averaged over
     the  machine's  run time.  The use of -c presents successive
lines averaged
     over the wait period.  The -I option causes iostat to  print
raw, unaveraged
 values.

     The options are as follows:

     -c       Repeat the display count times.  Unless the -I flag
is in effect,
             the first display is for the time since a reboot and
each subsequent
  report  is for the time period since the last
display.  If
             no wait interval is specified, the default is 1 second.

     -C      Show CPU statistics.  This is enabled by default unless the -d,
             -D, or -T flags are used.

     -d      Show disk statistics.  This is  the  default.   Displays kilobytes
             per  transfer,  number  of  transfers, and megabytes
transferred.
             Use of this flag disables display  of  CPU  and  tty
statistics.

     -D       Show alternate disk statistics.  Displays kilobytes
transferred,
             number of transfers, and time  spent  in  transfers.
Use of this
             flag disables the default display.

     -I       Show the running total values, rather than an average.

     -M      Extract values associated with the  name  list  from
the specified
             core instead of the default ``/dev/mem''.

     -N       Extract the name list from the specified system instead of the
             default ``/bsd''.

     -T      Show tty statistics.  This is enabled by default unless the -C,
             -d, or -D flags are used.

     -w       Pause wait seconds between each display.  If no repeat count is
             specified, the default is infinity.

     iostat displays its information in the following format:

     tty
           tin     characters read from terminals
           tout    characters written to terminals

     disks
           Disk operations.  The header of the field is the  disk
name and unit
           number.   If more than four disk drives are configured
in the system,
 iostat displays only the first four  drives.   To
force iostat
           to  display  specific  drives, their names may be supplied on the command
 line.

           KB/t    Kilobytes transferred per disk transfer
           t/s     Transfers per second
           MB/s    Megabytes transferred per second

           The alternate display format, (selected with -D), presents the following
 values:

           KB      Kilobytes transferred
           xfr     Disk transfers
           time    Seconds spent in disk activity

     cpu
           us      % of CPU time in user mode
           ni       % of CPU time in user mode running niced processes
           sy      % of CPU time in system mode
           in      % of CPU time processing interrupts
           id      % of CPU time in idle mode

FILES    [Toc]    [Back]

     /bsd      default kernel namelist
     /dev/mem  default memory file

SEE ALSO    [Toc]    [Back]

     fstat(1),   netstat(1),   nfsstat(1),   ps(1),    systat(1),
pstat(8), vmstat(8)

     The  sections starting with ``Interpreting system activity''
in Installing
     and Operating 4.3BSD.

OpenBSD     3.6                        January      18,      1996