516 lines
13 KiB
Groff
516 lines
13 KiB
Groff
.\"
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.\" Copyright (c) 1997 Kenneth D. Merry.
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. The name of the author may not be used to endorse or promote products
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.\" derived from this software without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.\" Copyright (c) 1985, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)iostat.8 8.1 (Berkeley) 6/6/93
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.\"
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.Dd December 15, 2012
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.Dt IOSTAT 8
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.Os
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.Sh NAME
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.Nm iostat
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.Nd report
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.Tn I/O
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statistics
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.Sh SYNOPSIS
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.Nm
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.Op Fl CdhIKoTxz?\&
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.Op Fl c Ar count
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.Op Fl M Ar core
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.Op Fl n Ar devs
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.Op Fl N Ar system
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.Oo
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.Fl t
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.Sm off
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.Ar type , if , pass
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.Sm on
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.Oc
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.Op Fl w Ar wait
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.Op Ar drives
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.Sh DESCRIPTION
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The
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.Nm
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utility displays kernel
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.Tn I/O
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statistics on terminal, device and cpu operations.
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The first statistics that are printed are averaged over the system uptime.
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To get information about the current activity, a suitable wait time should
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be specified, so that the subsequent sets of printed statistics will be
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averaged over that time.
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.Pp
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The options are as follows:
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.Bl -tag -width flag
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.It Fl c
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Repeat the display
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.Ar count
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times.
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If no repeat
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.Ar count
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is specified, the default depends on whether
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.Fl w
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is specified.
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With
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.Fl w
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the default repeat count is infinity, otherwise it is 1.
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.It Fl C
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Display CPU statistics.
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This is on by default, unless
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.Fl d
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or
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.Fl x
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is specified.
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.It Fl d
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Display only device statistics.
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If this flag is turned on, only device statistics will be displayed, unless
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.Fl C
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or
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.Fl T
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is also specified to enable the display of CPU or TTY statistics.
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.It Fl h
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Put
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.Nm
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in
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.Sq top
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mode.
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In this mode,
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.Nm
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will show devices in order from highest to lowest bytes
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per measurement cycle.
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.It Fl I
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Display total statistics for a given time period, rather than average
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statistics for each second during that time period.
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.It Fl K
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In the blocks transferred display (-o), display block count in kilobytes rather
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then the device native block size.
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.It Fl M
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Extract values associated with the name list from the specified core
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instead of the default
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.Dq Pa /dev/kmem .
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.It Fl n
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Display up to
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.Ar devs
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number of devices.
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The
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.Nm
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utility will display fewer devices if there are not
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.Ar devs
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devices present.
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.It Fl N
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Extract the name list from the specified system instead of the default
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.Dq Pa /boot/kernel/kernel .
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.It Fl o
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Display old-style
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.Nm
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device statistics.
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Sectors per second, transfers per second, and milliseconds per seek are
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displayed.
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If
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.Fl I
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is specified, total blocks/sectors, total transfers, and
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milliseconds per seek are displayed.
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.It Fl t
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Specify which types of devices to display.
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There are three different categories of devices:
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.Pp
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.Bl -tag -width indent -compact
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.It device type:
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.Bl -tag -width 9n -compact
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.It da
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Direct Access devices
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.It sa
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Sequential Access devices
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.It printer
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Printers
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.It proc
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Processor devices
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.It worm
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Write Once Read Multiple devices
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.It cd
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CD devices
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.It scanner
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Scanner devices
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.It optical
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Optical Memory devices
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.It changer
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Medium Changer devices
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.It comm
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Communication devices
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.It array
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Storage Array devices
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.It enclosure
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Enclosure Services devices
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.It floppy
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Floppy devices
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.El
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.Pp
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.It interface:
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.Bl -tag -width 9n -compact
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.It IDE
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Integrated Drive Electronics devices
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.It SCSI
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Small Computer System Interface devices
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.It other
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Any other device interface
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.El
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.Pp
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.It passthrough:
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.Bl -tag -width 9n -compact
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.It pass
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Passthrough devices
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.El
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.El
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.Pp
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The user must specify at least one device type, and may specify at most
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one device type from each category.
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Multiple device types in a single device type statement must be separated by
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commas.
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.Pp
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Any number of
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.Fl t
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arguments may be specified on the command line.
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All
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.Fl t
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arguments are ORed together to form a matching expression against which
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all devices in the system are compared.
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Any device that fully matches any
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.Fl t
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argument will be included in the
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.Nm
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output, up to the number of devices that can be displayed in
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80 columns, or the maximum number of devices specified by the user.
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.It Fl T
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Display TTY statistics.
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This is on by default, unless
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.Fl d
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or
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.Fl x
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is specified.
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.It Fl w
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Pause
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.Ar wait
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seconds between each display.
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If no
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.Ar wait
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interval is specified, the default is 1 second.
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.Pp
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The
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.Nm
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command will accept and honor a non-integer number of seconds.
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Note that the interval only has millisecond granularity.
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Finer values will be truncated.
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E.g.,
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.Dq Li -w1.0001
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is the same as
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.Dq Li -w1.000 .
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The interval will also suffer from modifications to
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.Va kern.hz
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so your mileage may vary.
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.It Fl x
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Show extended disk statistics.
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Each disk is displayed on a line of its own with all available statistics.
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If this flag is turned on, only disk statistics will be displayed, unless
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.Fl C
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or
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.Fl T
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is also specified to enable the display of CPU or TTY statistics.
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.It Fl z
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If
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.Fl x
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is specified, omit lines for devices with no activity.
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.It Fl ?\&
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Display a usage statement and exit.
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.El
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.Pp
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The
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.Nm
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utility displays its information in the following format:
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.Bl -tag -width flag
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.It tty
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.Bl -tag -width indent -compact
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.It tin
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characters read from terminals
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.It tout
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characters written to terminals
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.El
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.It devices
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Device operations.
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The header of the field is the device name and unit number.
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The
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.Nm
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utility
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will display as many devices as will fit in a standard 80 column screen, or
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the maximum number of devices in the system, whichever is smaller.
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If
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.Fl n
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is specified on the command line,
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.Nm
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will display the smaller of the
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requested number of devices, and the maximum number of devices in the system.
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To force
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.Nm
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to display specific drives, their names may be supplied on the command
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line.
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The
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.Nm
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utility
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will not display more devices than will fit in an 80 column screen, unless
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the
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.Fl n
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argument is given on the command line to specify a maximum number of
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devices to display.
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If fewer devices are specified on the command line than will fit in an 80
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column screen,
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.Nm
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will show only the specified devices.
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.Pp
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The standard
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.Nm
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device display shows the following statistics:
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.Pp
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.Bl -tag -width indent -compact
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.It KB/t
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kilobytes per transfer
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.It tps
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transfers per second
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.It MB/s
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megabytes per second
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.El
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.Pp
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The standard
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.Nm
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device display, with the
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.Fl I
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flag specified, shows the following statistics:
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.Pp
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.Bl -tag -width indent -compact
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.It KB/t
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kilobytes per transfer
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.It xfrs
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total number of transfers
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.It MB
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total number of megabytes transferred
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.El
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.Pp
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The extended
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.Nm
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device display, with the
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.Fl x
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flag specified, shows the following statistics:
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.Pp
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.Bl -tag -width indent -compact
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.It r/s
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read operations per second
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.It w/s
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write operations per second
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.It kr/s
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kilobytes read per second
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.It kw/s
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kilobytes write per second
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.It qlen
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transactions queue length
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.It svc_t
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average duration of transactions, in milliseconds
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.It %b
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% of time the device had one or more outstanding transactions
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.El
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.Pp
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The extended
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.Nm
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device display, with the
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.Fl x
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and
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.Fl I
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flags specified, shows the following statistics:
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.Pp
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.Bl -tag -width indent -compact
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.It r/i
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read operations per time period
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.It w/i
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write operations per time period
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.It kr/i
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kilobytes read per time period
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.It kw/i
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kilobytes write per time period
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.It qlen
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transactions queue length
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.It tsvc_t/i
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total duration of transactions per time period, in seconds
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.It sb/i
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total time the device had one or more outstanding transactions per
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time period, in seconds
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.El
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.Pp
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The old-style
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.Nm
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display (using
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.Fl o )
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shows the following statistics:
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.Pp
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.Bl -tag -width indent -compact
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.It sps
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sectors transferred per second
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.It tps
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transfers per second
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.It msps
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average milliseconds per transaction
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.El
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.Pp
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The old-style
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.Nm
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display, with the
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.Fl I
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flag specified, shows the following statistics:
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.Pp
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.Bl -tag -width indent -compact
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.It blk
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total blocks/sectors transferred
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.It xfr
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total transfers
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.It msps
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average milliseconds per transaction
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.El
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.It cpu
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.Bl -tag -width indent -compact
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.It \&us
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% of cpu time in user mode
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.It \&ni
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% of cpu time in user mode running niced processes
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.It \&sy
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% of cpu time in system mode
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.It \&in
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% of cpu time in interrupt mode
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.It \&id
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% of cpu time in idle mode
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.El
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.El
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.Sh FILES
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.Bl -tag -width /boot/kernel/kernel -compact
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.It Pa /boot/kernel/kernel
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Default kernel namelist.
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.It Pa /dev/kmem
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Default memory file.
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.El
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.Sh EXAMPLES
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.Dl iostat -w 1 da0 da1 cd0
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.Pp
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Display statistics for the first two Direct Access devices and the first
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CDROM device every second ad infinitum.
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.Pp
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.Dl iostat -c 2
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.Pp
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Display the statistics for the first four devices in the system twice, with
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a one second display interval.
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.Pp
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.Dl iostat -t da -t cd -w 1
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.Pp
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Display statistics for all CDROM and Direct Access devices every second
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ad infinitum.
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.Pp
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.Dl iostat -t da,scsi,pass -t cd,scsi,pass
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.Pp
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Display statistics once for all SCSI passthrough devices that provide access
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to either Direct Access or CDROM devices.
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.Pp
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.Dl iostat -h -n 8 -w 1
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.Pp
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Display up to 8 devices with the most I/O every second ad infinitum.
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.Pp
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.Dl iostat -dh -t da -w 1
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.Pp
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Omit the TTY and CPU displays, show devices in order of performance and
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show only Direct Access devices every second ad infinitum.
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.Pp
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.Dl iostat -Iw 3
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.Pp
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Display total statistics every three seconds ad infinitum.
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.Pp
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.Dl iostat -odICTw 2 -c 9
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.Pp
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Display total statistics using the old-style output format 9 times, with
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a two second interval between each measurement/display.
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The
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.Fl d
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flag generally disables the TTY and CPU displays, but since the
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.Fl T
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and
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.Fl C
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flags are given, the TTY and CPU displays will be displayed.
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.Sh SEE ALSO
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.Xr fstat 1 ,
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.Xr netstat 1 ,
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.Xr nfsstat 1 ,
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.Xr ps 1 ,
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.Xr systat 1 ,
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.Xr devstat 3 ,
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.Xr gstat 8 ,
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.Xr pstat 8 ,
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.Xr vmstat 8
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.Pp
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The sections starting with ``Interpreting system activity'' in
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.%T "Installing and Operating 4.3BSD" .
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.Sh HISTORY
|
|
This version of
|
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.Nm
|
|
first appeared in
|
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.Fx 3.0 .
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.Sh AUTHORS
|
|
.An Kenneth Merry Aq Mt ken@FreeBSD.org
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.Sh BUGS
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|
The use of
|
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.Nm
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|
as a debugging tool for crash dumps is probably limited because there is
|
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currently no way to get statistics that only cover the time immediately before
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the crash.
|