1.\" $NetBSD: iostat.8,v 1.24 2015/07/09 13:26:52 mrg Exp $ 2.\" 3.\" Copyright (c) 1985, 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" from: @(#)iostat.8 8.1 (Berkeley) 6/6/93 31.\" 32.Dd July 9, 2015 33.Dt IOSTAT 8 34.Os 35.Sh NAME 36.Nm iostat 37.Nd report 38.Tn I/O 39statistics 40.Sh SYNOPSIS 41.Nm 42.Op Fl CdDITx 43.Op Fl c Ar count 44.Op Fl w Ar wait 45.Op Ar drives 46.Sh DESCRIPTION 47.Nm 48displays kernel 49.Tn I/O 50statistics on terminal, disk and CPU operations. 51By default, 52.Nm 53displays one line of statistics averaged over the machine's run time. 54The use of 55.Fl c 56presents successive lines averaged over the 57.Ar wait 58period. 59The 60.Fl I 61option causes 62.Nm 63to print raw, unaveraged values. 64.Pp 65Only the last disk option specified 66.Fl ( d , 67.Fl D , 68or 69.Fl x ) 70is used. 71.Pp 72The options are as follows: 73.Bl -tag -width XNXsystemX 74.It Fl c Ar count 75Repeat the display 76.Ar count 77times. 78Unless the 79.Fl I 80flag is in effect, the first display is for the time since a reboot and 81each subsequent report is for the time period since the last display. 82If no 83.Ar wait 84interval is specified, the default is 1 second. 85.It Fl C 86Show CPU statistics. 87This is enabled by default unless the 88.Fl d , 89.Fl D , 90.Fl T , 91or 92.Fl x 93flags are used. 94.It Fl d 95Show disk statistics. 96This is the default. 97Displays kilobytes per 98transfer, number of transfers, and megabytes transferred. 99Use of this flag disables display of CPU and tty statistics. 100.It Fl D 101Show alternative disk statistics. 102Displays kilobytes transferred, number of 103transfers, and time spent in transfers. 104Use of this flag disables the default display. 105.It Fl I 106Show the running total values, rather than an average. 107.It Fl T 108Show tty statistics. 109This is enabled by default unless the 110.Fl C , 111.Fl d , 112or 113.Fl D 114flags are used. 115.It Fl w Ar wait 116Pause 117.Ar wait 118seconds between each display. 119If no repeat 120.Ar count 121is specified, the default is infinity. 122.It Fl x 123Show extended disk statistics. 124Each disk is displayed on a line of its own with all available 125statistics. 126This option overrides all other display options, and all 127disks are displayed unless specific disks 128are provided as arguments. 129Additionally, separate read and write statistics are displayed. 130.El 131.Pp 132.Nm 133displays its information in the following format: 134.Bl -tag -width flag 135.It tty 136.Bl -tag -width indent -compact 137.It tin 138characters read from terminals 139.It tout 140characters written to terminals 141.El 142.It disks 143Disk operations. 144The header of the field is the disk name and unit number. 145If more drives are configured in the system that fit across the 146current display, 147.Nm 148displays only those drives that fit on the display. 149To force 150.Nm 151to display specific drives, they may be supplied on the command 152line, either as names or 153.Fn fnmatch 154patterns. 155.Pp 156.Bl -tag -width indent -compact 157.It KB/t 158Kilobytes transferred per disk transfer 159.It t/s 160transfers per second 161.It MB/s 162Megabytes transferred per second 163.Pp 164.El 165The alternative display format, (selected with 166.Fl D ) , 167presents the following values. 168.Bl -tag -width indent -compact 169.It KB 170Kilobytes transferred 171.It xfr 172Disk transfers 173.It time 174Seconds spent in disk activity 175.El 176.It cpu 177.Bl -tag -width indent -compact 178.It \&us 179% of CPU time in user mode 180.It \&ni 181% of CPU time in user mode running niced processes 182.It \&sy 183% of CPU time in system mode 184.It \&id 185% of CPU time in idle mode 186.El 187.El 188.Sh SEE ALSO 189.Xr fstat 1 , 190.Xr netstat 1 , 191.Xr nfsstat 1 , 192.Xr \&ps 1 , 193.Xr systat 1 , 194.Xr vmstat 1 , 195.Xr fnmatch 3 , 196.Xr pstat 8 197.Pp 198The sections starting with ``Interpreting system activity'' in 199.%T "Installing and Operating 4.3BSD" . 200.Sh HISTORY 201.Nm 202appeared in 203.At v6 . 204The 205.Fl x 206option was added in 207.Nx 1.4 . 208