IOSTAT(8) | System Manager's Manual | IOSTAT(8) |
iostat
— report
I/O statistics
iostat |
[-CUdKIoT? ] [-c
count] [-n
devs] [-w
wait] [drives] |
The iostat
utility displays kernel I/O
statistics on terminal, device and cpu operations. The first statistics that
are printed are averaged over the system uptime. To get information about
the current activity, a suitable wait time should be specified, so that the
subsequent sets of printed statistics will be averaged over that time.
The options are as follows:
-?
-c
-C
-d
is specified.-d
-C
or
-U
or -T
is also specified
to enable the display of CPU, load average or TTY statistics.-I
-K
-n
iostat
utility will display fewer devices if there
are not devs devices present.-o
iostat
device statistics.
Sectors per second, transfers per second, and milliseconds per seek are
displayed. If -I
is specified, total
blocks/sectors, total transfers, and milliseconds per seek are
displayed.-T
-d
is specified.-U
-d
is specified.-w
The iostat
utility displays its
information in the following format:
iostat
utility will display as many
devices as will fit in a standard 80 column screen, or the maximum number
of devices in the system, whichever is smaller. If
-n
is specified on the command line,
iostat
will display the smaller of the requested
number of devices, and the maximum number of devices in the system. To
force iostat
to display specific drives, their
names may be supplied on the command line. The
iostat
utility will not display more devices than
will fit in an 80 column screen, unless the -n
argument is given on the command line to specify a maximum number of
devices to display, or the list of specified devices exceeds 80 columns.
If fewer devices are specified on the command line than will fit in an 80
column screen, iostat
will show only the specified
devices.
The standard iostat
device display
shows the following statistics:
The standard iostat
device display,
with the -I
flag specified, shows the following
statistics:
The old-style iostat
display (using
-o
) shows the following statistics:
The old-style iostat
display, with the
-I
flag specified, shows the following
statistics:
iostat -w 1 disk0 disk2
Display statistics for the first and third disk devices device every second ad infinitum.
iostat -c 2
Display the statistics for the first four devices in the system twice, with a one second display interval.
iostat -Iw 3
Display total statistics every three seconds ad infinitum.
iostat -odICTw 2 -c 9
Display total statistics using the old-style output format 9
times, with a two second interval between each measurement/display. The
-d
flag generally disables the TTY and CPU displays,
but since the -T
and -C
flags are given, the TTY and CPU displays will be displayed.
netstat(1), nfsstat(1), ps(1), top(1), vm_stat(1)
The sections starting with ``Interpreting system activity'' in Installing and Operating 4.3BSD.
This version of iostat
first appeared in
FreeBSD 3.0.
May 22, 2015 | macOS 14.6 |