2 .\" Copyright (c) 1997 Kenneth D. Merry.
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58 .\" @(#)iostat.8 8.1 (Berkeley) 6/6/93
85 statistics on terminal, device and cpu
88 The options are as follows:
96 interval is specified, the default is 1 second.
98 Display CPU statistics.
99 This is on by default, unless
103 Display only device statistics.
104 If this flag is turned on, only device statistics will be displayed, unless
108 is also specified to enable the display of CPU or TTY statistics.
110 Display more details.
111 If this flag is turned on, details on read and write statistics will be
112 displayed as MBw/s (Megabyte written per second), MBr/s (Megabyte read per second),
113 rtps (read transactions per second) and wtps (write transactions per second).
122 will show devices in order from highest to lowest bytes
123 per measurement cycle.
125 Display total statistics for a given time period, rather than average
126 statistics for each second during that time period.
128 In the blocks transferred display (-o), display block count in kilobytes rather
129 then the device native block size.
135 will display fewer devices if there aren't
142 Sectors per second, transfers per second, and milliseconds per seek are
146 is specified, total blocks/sectors, total transfers, and
147 milliseconds per seek are displayed.
149 Specify which types of devices to display.
150 There are three different categories of devices:
152 .Bl -tag -width indent -compact
154 .Bl -tag -width 9n -compact
156 Direct Access devices
158 Sequential Access devices
164 Write Once Read Multiple devices
170 Optical Memory devices
172 Medium Changer devices
174 Communication devices
176 Storage Array devices
178 Enclosure Services devices
184 .Bl -tag -width 9n -compact
186 Integrated Drive Electronics devices
188 Small Computer System Interface devices
190 Any other device interface
194 .Bl -tag -width 9n -compact
200 The user must specify at least one device type, and may specify at most
201 one device type from each category.
202 Multiple device types in a single device type statement must be separated by
207 arguments may be specified on the command line.
210 arguments are ORed together to form a matching expression against which
211 all devices in the system are compared.
212 Any device that fully matches any
214 argument will be included in the
216 output, up to the number of devices that can be displayed in
217 80 columns, or the maximum number of devices specified by the user.
219 Display TTY statistics.
220 This is on by default, unless
226 seconds between each display.
229 is specified, the default is infinity.
233 displays its information in the following format:
236 .Bl -tag -width indent -compact
238 characters read from terminals
240 characters written to terminals
244 The header of the field is the device name and unit number.
246 will display as many devices as will fit in a standard 80 column screen, or
247 the maximum number of devices in the system, whichever is smaller.
250 is specified on the command line,
252 will display the smaller of the
253 requested number of devices, and the maximum number of devices in the system.
256 to display specific drives, their names may be supplied on the command
259 will not display more devices than will fit in an 80 column screen, unless
262 argument is given on the command line to specify a maximum number of
264 If fewer devices are specified on the command line than will fit in an 80
267 will show only the specified devices.
271 device display shows the following statistics:
273 .Bl -tag -width indent -compact
275 kilobytes per transfer
284 device display, with the
286 flag specified, shows the following statistics:
288 .Bl -tag -width indent -compact
290 kilobytes per transfer
292 total number of transfers
294 total number of megabytes transferred
301 shows the following statistics:
303 .Bl -tag -width indent -compact
305 sectors transferred per second
309 average milliseconds per transaction
316 flag specified, shows the following statistics:
318 .Bl -tag -width indent -compact
320 total blocks/sectors transferred
324 average milliseconds per transaction
327 .Bl -tag -width indent -compact
329 % of cpu time in user mode
331 % of cpu time in user mode running niced processes
333 % of cpu time in system mode
335 % of cpu time in interrupt mode
337 % of cpu time in idle mode
341 .Dl iostat -w 1 da0 da1 cd0
343 Display statistics for the first two Direct Access devices and the first
344 CDROM device every second ad infinitum.
348 Display the statistics for the first four devices in the system twice, with
349 a one second display interval.
351 .Dl iostat -t da -t cd -w 1
353 Display statistics for all CDROM and Direct Access devices every second
356 .Dl iostat -t da,scsi,pass -t cd,scsi,pass
358 Display statistics once for all SCSI passthrough devices that provide access
359 to either Direct Access or CDROM devices.
361 .Dl iostat -h -n 8 -w 1
363 Display up to 8 devices with the most I/O every second ad infinitum.
365 .Dl iostat -dh -t da -w 1
367 Omit the TTY and CPU displays, show devices in order of performance and
368 show only Direct Access devices every second ad infinitum.
372 Display total statistics every three seconds ad infinitum.
374 .Dl iostat -odICTw 2 -c 9
376 Display total statistics using the old-style output format 9 times, with
377 a two second interval between each measurement/display.
380 flag generally disables the TTY and CPU displays, but since the
384 flags are given, the TTY and CPU displays will be displayed.
394 The sections starting with ``Interpreting system activity'' in
395 .%T "Installing and Operating 4.3BSD" .
402 .An Kenneth Merry Aq ken@FreeBSD.org