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NetBSD 6.1.5 - man page for iostat (netbsd section 8)

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

NAME
     iostat -- report I/O statistics

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

DESCRIPTION
     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.

     Only the last disk option specified (-d, -D, or -x) is used.

     The options are as follows:

     -c count	 Repeat the display count times.  Unless the -I flag is in effect, the first dis-
		 play 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, -T, or -x
		 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 dis-
		 play of CPU and tty statistics.

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

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

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

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

     -x 	 Show extended disk statistics.  Each disk is displayed on a line of its own with
		 all available statistics.  This option overrides all other display options, and
		 all disks are displayed unless specific disks are provided as arguments.  Addi-
		 tionally, separate read and write statistics are displayed.

     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 alternative 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
	   id	   % of CPU time in idle mode

FILES
     /netbsd   Default kernel namelist.
     /dev/mem  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.

HISTORY
     iostat appeared in Version 6 AT&T UNIX.  The -x option was added in NetBSD 1.4.

BSD					  March 1, 2003 				      BSD


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