1.\" $NetBSD: iostat.8,v 1.16 2001/07/08 18:19:16 wiz 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. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" from: @(#)iostat.8 8.1 (Berkeley) 6/6/93 35.\" 36.Dd August 25, 1998 37.Dt IOSTAT 8 38.Os 39.Sh NAME 40.Nm iostat 41.Nd report 42.Tn I/O 43statistics 44.Sh SYNOPSIS 45.Nm 46.Op Fl CdDITx 47.Op Fl c Ar count 48.Op Fl M Ar core 49.Op Fl N Ar system 50.Op Fl w Ar wait 51.Op Ar drives 52.Sh DESCRIPTION 53.Nm 54displays kernel 55.Tn I/O 56statistics on terminal, disk and CPU operations. By default, 57.Nm 58displays one line of statistics averaged over the machine's run time. 59The use of 60.Fl c 61presents successive lines averaged over the 62.Ar wait 63period. 64The 65.Fl I 66option causes 67.Nm 68to print raw, unaveraged values. 69.Pp 70Only the last disk option specified 71.Fl ( d , 72.Fl D , 73or 74.Fl x ) 75is used. 76.Pp 77The options are as follows: 78.Bl -tag -width flag 79.It Fl c 80Repeat the display 81.Ar count 82times. 83Unless the 84.Fl I 85flag is in effect, the first display is for the time since a reboot and 86each subsequent report is for the time period since the last display. 87If no 88.Ar wait 89interval is specified, the default is 1 second. 90.It Fl C 91Show CPU statistics. This is enabled by default unless the 92.Fl d , 93.Fl D , 94.Fl T , 95or 96.Fl x 97flags are used. 98.It Fl d 99Show disk statistics. This is the default. Displays kilobytes per 100transfer, number of transfers, and megabytes transferred. Use of this 101flag disables display of CPU and tty statistics. 102.It Fl D 103Show alternative disk statistics. Displays kilobytes transferred, number of 104transfers, and time spent in transfers. Use of this flag disables the 105default display. 106.It Fl I 107Show the running total values, rather than an average. 108.It Fl M 109Extract values associated with the name list from the specified core 110instead of the default 111.Dq Pa /dev/mem . 112.It Fl N 113Extract the name list from the specified system instead of the default 114.Dq Pa /netbsd . 115.It Fl T 116Show tty statistics. This is enabled by default unless the 117.Fl C , 118.Fl d , 119or 120.Fl D 121flags are used. 122.It Fl w 123Pause 124.Ar wait 125seconds between each display. 126If no repeat 127.Ar count 128is specified, the default is infinity. 129.It Fl x 130Show extended disk statistics. 131Each disk is displayed on a line of its own with all available 132statistics. 133This option overrides all other display options, and all 134disks are displayed regardless of whether specific disks 135are provided as arguments. 136.El 137.Pp 138.Nm 139displays its information in the following format: 140.Bl -tag -width flag 141.It tty 142.Bl -tag -width indent -compact 143.It tin 144characters read from terminals 145.It tout 146characters written to terminals 147.El 148.It disks 149Disk operations. 150The header of the field is the disk name and unit number. 151If more than four disk drives are configured in the system, 152.Nm 153displays only the first four drives. 154To force 155.Nm 156to display specific drives, their names may be supplied on the command 157line. 158.Pp 159.Bl -tag -width indent -compact 160.It KB/t 161Kilobytes transferred per disk transfer 162.It t/s 163transfers per second 164.It MB/s 165Megabytes transferred per second 166.Pp 167.El 168The alternative display format, (selected with 169.Fl D ) , 170presents the following values. 171.Bl -tag -width indent -compact 172.It KB 173Kilobytes transferred 174.It xfr 175Disk transfers 176.It time 177Seconds spent in disk activity 178.El 179.It cpu 180.Bl -tag -width indent -compact 181.It \&us 182% of CPU time in user mode 183.It \&ni 184% of CPU time in user mode running niced processes 185.It \&sy 186% of CPU time in system mode 187.It \&id 188% of CPU time in idle mode 189.El 190.El 191.Sh FILES 192.Bl -tag -width /dev/mem -compact 193.It Pa /netbsd 194Default kernel namelist. 195.It Pa /dev/mem 196Default memory file. 197.El 198.Sh SEE ALSO 199.Xr fstat 1 , 200.Xr netstat 1 , 201.Xr nfsstat 1 , 202.Xr \&ps 1 , 203.Xr systat 1 , 204.Xr vmstat 1 , 205.Xr pstat 8 206.Pp 207The sections starting with ``Interpreting system activity'' in 208.%T "Installing and Operating 4.3BSD" . 209.Sh HISTORY 210.Nm 211appeared in 212.At v6 . 213The 214.Fl x 215option was added in 216.Nx 1.4 . 217