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IOSTAT(8)                 BSD System Manager's Manual                IOSTAT(8)

NAME
     iostat - report I/O statistics

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

DESCRIPTION
     Iostat displays kernel I/O statistics on terminal, disk and cpu opera-
     tions.

     The options are as follows:

     -c    Repeat the display count times.  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 de-
           fault is 1 second.

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

     -N    Extract the name list from the specified system instead of the de-
           fault ``/vmunix''.

     -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 (this field is system dependent).  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.

           sps     sectors transferred per second
           tps     transfers per second
           msps    milliseconds per average seek (including implied seeks and
                   rotational latency)

     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
           id      % of cpu time in idle mode

FILES
     /vmunix    Default kernel namelist.
     /dev/kmem  Default memory file.

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

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

4th Berkeley Distribution        June 6, 1993                                1