2 .\" Copyright (c) 1997 Kenneth D. Merry.
3 .\" All rights reserved.
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28 .\" $FreeBSD: src/usr.sbin/iostat/iostat.8,v 1.11.2.9 2002/12/29 16:35:41 schweikh Exp $
29 .\" $DragonFly: src/usr.sbin/iostat/iostat.8,v 1.4 2005/09/01 19:08:38 swildner Exp $
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62 .\" @(#)iostat.8 8.1 (Berkeley) 6/6/93
89 statistics on terminal, device and cpu
92 The options are as follows:
100 interval is specified, the default is 1 second.
102 Display CPU statistics.
103 This is on by default, unless
107 Display only device statistics.
108 If this flag is turned on, only device statistics will be displayed, unless
112 is also specified to enable the display of CPU or TTY statistics.
114 Display more details.
115 If this flag is turned on, details on read and write statistics will be
116 displayed as MBw/s (Megabyte written per second), MBr/s (Megabyte read per second),
117 rtps (read transactions per second) and wtps (write transactions per second).
126 will show devices in order from highest to lowest bytes
127 per measurement cycle.
129 Display total statistics for a given time period, rather than average
130 statistics for each second during that time period.
132 In the blocks transferred display (-o), display block count in kilobytes rather
133 then the device native block size.
139 will display fewer devices if there aren't
146 Sectors per second, transfers per second, and milliseconds per seek are
150 is specified, total blocks/sectors, total transfers, and
151 milliseconds per seek are displayed.
153 Specify which types of devices to display.
154 There are three different categories of devices:
156 .Bl -tag -width indent -compact
158 .Bl -tag -width 9n -compact
160 Direct Access devices
162 Sequential Access devices
168 Write Once Read Multiple devices
174 Optical Memory devices
176 Medium Changer devices
178 Communication devices
180 Storage Array devices
182 Enclosure Services devices
188 .Bl -tag -width 9n -compact
190 Integrated Drive Electronics devices
192 Small Computer System Interface devices
194 Any other device interface
198 .Bl -tag -width 9n -compact
204 The user must specify at least one device type, and may specify at most
205 one device type from each category.
206 Multiple device types in a single device type statement must be separated by
211 arguments may be specified on the command line.
214 arguments are ORed together to form a matching expression against which
215 all devices in the system are compared.
216 Any device that fully matches any
218 argument will be included in the
220 output, up to the number of devices that can be displayed in
221 80 columns, or the maximum number of devices specified by the user.
223 Display TTY statistics.
224 This is on by default, unless
230 seconds between each display.
233 is specified, the default is infinity.
237 displays its information in the following format:
240 .Bl -tag -width indent -compact
242 characters read from terminals
244 characters written to terminals
248 The header of the field is the device name and unit number.
250 will display as many devices as will fit in a standard 80 column screen, or
251 the maximum number of devices in the system, whichever is smaller.
254 is specified on the command line,
256 will display the smaller of the
257 requested number of devices, and the maximum number of devices in the system.
260 to display specific drives, their names may be supplied on the command
263 will not display more devices than will fit in an 80 column screen, unless
266 argument is given on the command line to specify a maximum number of
268 If fewer devices are specified on the command line than will fit in an 80
271 will show only the specified devices.
275 device display shows the following statistics:
277 .Bl -tag -width indent -compact
279 kilobytes per transfer
288 device display, with the
290 flag specified, shows the following statistics:
292 .Bl -tag -width indent -compact
294 kilobytes per transfer
296 total number of transfers
298 total number of megabytes transferred
305 shows the following statistics:
307 .Bl -tag -width indent -compact
309 sectors transferred per second
313 average milliseconds per transaction
320 flag specified, shows the following statistics:
322 .Bl -tag -width indent -compact
324 total blocks/sectors transferred
328 average milliseconds per transaction
331 .Bl -tag -width indent -compact
333 % of cpu time in user mode
335 % of cpu time in user mode running niced processes
337 % of cpu time in system mode
339 % of cpu time in interrupt mode
341 % of cpu time in idle mode
345 .Dl iostat -w 1 da0 da1 cd0
347 Display statistics for the first two Direct Access devices and the first
348 CDROM device every second ad infinitum.
352 Display the statistics for the first four devices in the system twice, with
353 a one second display interval.
355 .Dl iostat -t da -t cd -w 1
357 Display statistics for all CDROM and Direct Access devices every second
360 .Dl iostat -t da,scsi,pass -t cd,scsi,pass
362 Display statistics once for all SCSI passthrough devices that provide access
363 to either Direct Access or CDROM devices.
365 .Dl iostat -h -n 8 -w 1
367 Display up to 8 devices with the most I/O every second ad infinitum.
369 .Dl iostat -dh -t da -w 1
371 Omit the TTY and CPU displays, show devices in order of performance and
372 show only Direct Access devices every second ad infinitum.
376 Display total statistics every three seconds ad infinitum.
378 .Dl iostat -odICTw 2 -c 9
380 Display total statistics using the old-style output format 9 times, with
381 a two second interval between each measurement/display.
384 flag generally disables the TTY and CPU displays, but since the
388 flags are given, the TTY and CPU displays will be displayed.
398 The sections starting with ``Interpreting system activity'' in
399 .%T "Installing and Operating 4.3BSD" .
406 .An Kenneth Merry Aq ken@FreeBSD.org