1.\" Copyright (c) 1985, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)iostat.8 8.1 (Berkeley) 6/6/93 33.\" 34.Dd June 6, 1993 35.Dt IOSTAT 8 36.Os BSD 4 37.Sh NAME 38.Nm iostat 39.Nd report 40.Tn I/O 41statistics 42.Sh SYNOPSIS 43.Nm iostat 44.Op Fl c Ar count 45.Op Fl M Ar core 46.Op Fl N Ar system 47.Op Fl w Ar wait 48.Op Ar drives 49.Sh DESCRIPTION 50.Nm Iostat 51displays kernel 52.Tn I/O 53statistics on terminal, disk and cpu 54operations. 55.Pp 56The options are as follows: 57.Bl -tag -width flag 58.It Fl c 59Repeat the display 60.Ar count 61times. 62The first display is for the time since a reboot and each subsequent 63report is for the time period since the last display. 64If no 65.Ar wait 66interval is specified, the default is 1 second. 67.It Fl M 68Extract values associated with the name list from the specified core 69instead of the default 70.Dq Pa /dev/kmem . 71.It Fl N 72Extract the name list from the specified system instead of the default 73.Dq Pa /kernel . 74.It Fl w 75Pause 76.Ar wait 77seconds between each display. 78If no repeat 79.Ar count 80is specified, the default is infinity. 81.El 82.Pp 83.Nm Iostat 84displays its information in the following format: 85.Bl -tag -width flag 86.It tty 87.Bl -tag -width indent -compact 88.It tin 89characters read from terminals 90.It tout 91characters written to terminals 92.El 93.It disks 94Disk operations (this field is system dependent). 95The header of the field is the disk name and unit number. 96If more than four disk drives are configured in the system, 97.Nm iostat 98displays only the first four drives. 99To force 100.Nm iostat 101to display specific drives, their names may be supplied on the command 102line. 103.Pp 104.Bl -tag -width indent -compact 105.It sps 106sectors transferred per second 107.It tps 108transfers per second 109.It msps 110milliseconds per average seek (including implied 111seeks and rotational latency) 112.El 113.It cpu 114.Bl -tag -width indent -compact 115.It \&us 116% of cpu time in user mode 117.It \&ni 118% of cpu time in user mode running niced processes 119.It \&sy 120% of cpu time in system mode 121.It \&in 122% of cpu time in interrupt mode 123.It \&id 124% of cpu time in idle mode 125.El 126.El 127.Sh FILES 128.Bl -tag -width /dev/kmem -compact 129.It Pa /kernel 130Default kernel namelist. 131.It Pa /dev/kmem 132Default memory file. 133.El 134.Sh SEE ALSO 135.Xr fstat 1 , 136.Xr netstat 1 , 137.Xr nfsstat 1 , 138.Xr \&ps 1 , 139.Xr systat 1 , 140.Xr vmstat 1 , 141.Xr pstat 8 142.Pp 143The sections starting with ``Interpreting system activity'' in 144.%T "Installing and Operating 4.3BSD" . 145