iostat.8 (270d3d754aaf84a6427db275f9a121561af689ad) iostat.8 (8d2fbde5040bc61a6c4685c0b8db2289834bc353)
1.\"
2.\" Copyright (c) 1997 Kenneth D. Merry.
3.\" All rights reserved.
4.\"
5.\" Redistribution and use in source and binary forms, with or without
6.\" modification, are permitted provided that the following conditions
7.\" are met:
8.\" 1. Redistributions of source code must retain the above copyright
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10.\" 2. Redistributions in binary form must reproduce the above copyright
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17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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26.\" SUCH DAMAGE.
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28.\" $Id$
29.\"
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
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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.\"
30.\" Copyright (c) 1985, 1991, 1993
31.\" The Regents of the University of California. All rights reserved.
32.\"
33.\" Redistribution and use in source and binary forms, with or without
34.\" modification, are permitted provided that the following conditions
35.\" are met:
36.\" 1. Redistributions of source code must retain the above copyright
37.\" notice, this list of conditions and the following disclaimer.

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55.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
56.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
57.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
58.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
59.\" SUCH DAMAGE.
60.\"
61.\" @(#)iostat.8 8.1 (Berkeley) 6/6/93
62.\"
34.Dd June 6, 1993
63.Dd December 22, 1997
35.Dt IOSTAT 8
64.Dt IOSTAT 8
36.Os BSD 4
65.Os FreeBSD 3.0
37.Sh NAME
38.Nm iostat
39.Nd report
40.Tn I/O
41statistics
42.Sh SYNOPSIS
43.Nm iostat
66.Sh NAME
67.Nm iostat
68.Nd report
69.Tn I/O
70statistics
71.Sh SYNOPSIS
72.Nm iostat
73.Op Fl CdhIoT?
44.Op Fl c Ar count
45.Op Fl M Ar core
74.Op Fl c Ar count
75.Op Fl M Ar core
76.Op Fl n Ar devs
46.Op Fl N Ar system
77.Op Fl N Ar system
78.Op Fl t Ar type,if,pass
47.Op Fl w Ar wait
48.Op Ar drives
49.Sh DESCRIPTION
50.Nm Iostat
51displays kernel
52.Tn I/O
79.Op Fl w Ar wait
80.Op Ar drives
81.Sh DESCRIPTION
82.Nm Iostat
83displays kernel
84.Tn I/O
53statistics on terminal, disk and cpu
85statistics on terminal, device 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
86operations.
87.Pp
88The options are as follows:
89.Bl -tag -width flag
90.It Fl c
91Repeat the display
92.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
93times. If no
65.Ar wait
66interval is specified, the default is 1 second.
94.Ar wait
95interval is specified, the default is 1 second.
96.It Fl C
97Display CPU statistics. This is on by default, unless
98.Fl d
99is specified.
100.It Fl d
101Display only device statistics. If this flag is turned on, only device
102statistics will be displayed, unless
103.Fl C
104or
105.Fl T
106is also specfied to enable the display of CPU or TTY statistics.
107.It Fl h
108Put iostat in
109.Sq top
110mode. In this mode, iostat will show devices in order from highest to
111lowest bytes per measurement cycle.
112.It Fl I
113Display total statstics for a given time period, rather than average
114statistics for each second during that time period.
67.It Fl M
68Extract values associated with the name list from the specified core
69instead of the default
70.Dq Pa /dev/kmem .
115.It Fl M
116Extract values associated with the name list from the specified core
117instead of the default
118.Dq Pa /dev/kmem .
119.It Fl n
120Display up to
121.Ar devs
122number of devices.
123.Nm iostat
124will display fewer devices if there aren't
125.Ar devs
126devices present.
71.It Fl N
72Extract the name list from the specified system instead of the default
73.Dq Pa /kernel .
127.It Fl N
128Extract the name list from the specified system instead of the default
129.Dq Pa /kernel .
130.It Fl o
131Display old-style
132.Nm iostat
133device statistics. Sectors per second, transfers per second, and miliseconds
134per seek are displayed. If
135.Fl I
136is specified, total blocks/sectors, total transfers, and
137miliseconds per seek are displayed.
138.It Fl t
139Specify which types of devices to display. There are three different
140categories of devices:
141
142.Bl -tag -width indent -compact
143.It device type:
144.Bl -tag -width 123456789 -compact
145.It da
146Direct Access devices
147.It sa
148Sequential Access devices
149.It printer
150Printers
151.It proc
152Processor devices
153.It worm
154Write Once Read Multiple devices
155.It cd
156CD devices
157.It scanner
158Scanner devices
159.It optical
160Optical Memory devices
161.It changer
162Medium Changer devices
163.It comm
164Communication devices
165.It array
166Storage Array devices
167.It enclosure
168Enclosure Services devices
169.It floppy
170Floppy devices
171.El
172.Pp
173.It interface:
174.Bl -tag -width 123456789 -compact
175.It IDE
176Integrated Drive Electronics devices
177.It SCSI
178Small Computer System Interface devices
179.It other
180Any other device interface
181.El
182.Pp
183.It passthrough:
184.Bl -tag -width 123456789 -compact
185.It pass
186Passthrough devices
187.El
188.El
189.Pp
190The user must specify at least one device type, and may specify at most
191one device type from each category. Multiple device types in a single
192device type statement must be separated by commas.
193.Pp
194Any number of
195.Fl t
196arguments may be specified on the command line. All
197.Fl t
198arguments are ORed together to form a matching expression against which
199all devices in the system are compared. Any device that fully matches
200any
201.Fl t
202argument will be included in the
203.Nm iostat
204output, up to the number of devices that can be displayed in
20580 columns, or the maximum number of devices specified by the user.
206.It Fl T
207Display TTY statistics. This is on by default, unless
208.Fl d
209is specified.
74.It Fl w
75Pause
76.Ar wait
77seconds between each display.
78If no repeat
79.Ar count
80is specified, the default is infinity.
210.It Fl w
211Pause
212.Ar wait
213seconds between each display.
214If no repeat
215.Ar count
216is specified, the default is infinity.
217.It Fl ?
218Display a usage statement and exit.
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
219.El
220.Pp
221.Nm Iostat
222displays its information in the following format:
223.Bl -tag -width flag
224.It tty
225.Bl -tag -width indent -compact
226.It tin
227characters read from terminals
228.It tout
229characters written to terminals
230.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,
231.It devices
232Device operations. The header of the field is the device name and unit number.
97.Nm iostat
233.Nm iostat
98displays only the first four drives.
234will display as many devices as will fit in a standard 80 column screen, or
235the maximum number of devices in the system, whichever is smaller. If
236.Fl n
237is specified on the command line, iostat will display the smaller of the
238requested number of devices, and the maximum number of devices in the system.
99To force
100.Nm iostat
101to display specific drives, their names may be supplied on the command
102line.
239To force
240.Nm iostat
241to display specific drives, their names may be supplied on the command
242line.
243.Nm iostat
244will not display more devices than will fit in an 80 column screen, unless
245the
246.Fl n
247argument is given on the command line to specify a maximum number of
248devices to display. If fewer devices are specified on the command line
249than will fit in an 80 column screen, iostat will show only the specified
250devices.
103.Pp
251.Pp
252The standard
253.Nm iostat
254device display shows the following statistics:
255.Pp
104.Bl -tag -width indent -compact
256.Bl -tag -width indent -compact
257.It KB/t
258kilobytes per transfer
259.It tps
260transfers per second
261.It MB/s
262megabytes per second
263.El
264.Pp
265The standard
266.Nm iostat
267device display, with the
268.Fl I
269flag specified, shows the following statistics:
270.Pp
271.Bl -tag -width indent -compact
272.It KB/t
273kilobytes per transfer
274.It xfrs
275total number of transfers
276.It MB
277total number of megabytes transferred
278.El
279.Pp
280The old-style
281.Nm iostat
282display (using
283.Fl o )
284shows the following statistics:
285.Pp
286.Bl -tag -width indent -compact
105.It sps
106sectors transferred per second
107.It tps
108transfers per second
109.It msps
287.It sps
288sectors transferred per second
289.It tps
290transfers per second
291.It msps
110milliseconds per average seek (including implied
111seeks and rotational latency)
292average milliseconds per transaction
112.El
293.El
294.Pp
295The old-style
296.Nm iostat
297display, with the
298.Fl I
299flag specified, shows the following statistics:
300.Pp
301.Bl -tag -width indent -compact
302.It blk
303total blocks/sectors transferred
304.It xfr
305total transfers
306.It msps
307average milliseconds per transaction
308.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

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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
309.It cpu
310.Bl -tag -width indent -compact
311.It \&us
312% of cpu time in user mode
313.It \&ni
314% of cpu time in user mode running niced processes
315.It \&sy
316% of cpu time in system mode

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322.El
323.Sh FILES
324.Bl -tag -width /dev/kmem -compact
325.It Pa /kernel
326Default kernel namelist.
327.It Pa /dev/kmem
328Default memory file.
329.El
330.Sh EXAMPLES
331.Dl iostat -w 1 da0 da1 cd0
332.Pp
333Display statistics for the first two Direct Access devices and the first
334CDROM device every second ad infinitum.
335.Pp
336.Dl iostat -c 2
337.Pp
338Display the statistics for the first four devices in the system twice, with
339a one second display interval.
340.Pp
341.Dl iostat -t da -t cd -w 1
342.Pp
343Display statistics for all CDROM and Direct Access devices every second
344ad infinitum.
345.Pp
346.Dl iostat -t da,scsi,pass -t cd,scsi,pass
347.Pp
348Display statistics once for all SCSI passthrough devices that provide access
349to either Direct Access or CDROM devices.
350.Pp
351.Dl iostat -h -n 8 -w 1
352.Pp
353Display up to 8 devices with the most I/O every second ad inifitum.
354.Pp
355.Dl iostat -dh -t da -w 1
356.Pp
357Omit the TTY and CPU displays, show devices in order of performance and
358show only Direct Access devices every second ad infinitum.
359.Pp
360.Dl iostat -Iw 3
361.Pp
362Display total statistics every three seconds ad infinitum.
363.Pp
364.Dl iostat -odICTw 2 -c 9
365.Pp
366Display total statistics using the old-style output format 9 times, with
367a two second interval between each measurement/display. The
368.Fl d
369flag generally disables the TTY and CPU displays, but since the
370.Fl T
371and
372.Fl C
373flags are given, the TTY and CPU displays will be displayed.
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 pstat 8 ,
141.Xr vmstat 8
142.Pp
143The sections starting with ``Interpreting system activity'' in
144.%T "Installing and Operating 4.3BSD" .
374.Sh SEE ALSO
375.Xr fstat 1 ,
376.Xr netstat 1 ,
377.Xr nfsstat 1 ,
378.Xr ps 1 ,
379.Xr systat 1 ,
380.Xr pstat 8 ,
381.Xr vmstat 8
382.Pp
383The sections starting with ``Interpreting system activity'' in
384.%T "Installing and Operating 4.3BSD" .
385.Sh HISTORY
386This version of
387.Nm iostat
388first appeared in
389.Fx 3.0 .
390.Sh BUGS
391.Pp
392You cannot display device statistics for a non-running system, due to the
393fact that the new device statistics interface is accessible only via
394.Xr sysctl 3 ,
395which does not provide a way to access non-running systems.
396.Sh AUTHOR
397.An Kenneth Merry Aq ken@FreeBSD.ORG