Repeat the display count times. If no wait interval is specified, the default is 1 second.
-C
Display CPU statistics. This is on by default, unless -d is specified.
-d
Display only device statistics. If this flag is turned on, only device statistics will be displayed, unless -C or -T is also specified to enable the display of CPU or TTY statistics.
-h
Put iostat in 'top' mode. In this mode, iostat will show devices in order from highest to lowest bytes per measurement cycle.
-I
Display total statistics for a given time period, rather than average statistics for each second during that time period.
-K
In the blocks transferred display (-o), display block count in kilobytes rather then the device native block size.
-M
Extract values associated with the name list from the specified core instead of the default "/dev/kmem".
-n
Display up to devs number of devices. The iostat utility will display fewer devices if there are not devs devices present.
-N
Extract the name list from the specified system instead of the default "/boot/kernel/kernel".
-o
Display old-style 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
Specify which types of devices to display. There are three different categories of devices:
device type:
da
Direct Access devices
sa
Sequential Access devices
printer
Printers
proc
Processor devices
worm
Write Once Read Multiple devices
cd
CD devices
scanner
Scanner devices
optical
Optical Memory devices
changer
Medium Changer devices
comm
Communication devices
array
Storage Array devices
enclosure
Enclosure Services devices
floppy
Floppy devices
interface:
IDE
Integrated Drive Electronics devices
SCSI
Small Computer System Interface devices
other
Any other device interface
passthrough:
pass
Passthrough devices
The user must specify at least one device type, and may specify at most one device type from each category. Multiple device types in a single device type statement must be separated by commas.
Any number of -t arguments may be specified on the command line. All -t arguments are ORed together to form a matching expression against which all devices in the system are compared. Any device that fully matches any -t argument will be included in the iostat output, up to the number of devices that can be displayed in 80 columns, or the maximum number of devices specified by the user.
-T
Display TTY statistics. This is on by default, unless -d is specified.
-w
Pause wait seconds between each display. If no repeat count is specified, the default is infinity.
-?
Display a usage statement and exit.
The iostat utility displays its information in the following format:
tty
tin
characters read from terminals
tout
characters written to terminals
devices
Device operations. The header of the field is the device name and unit number. The 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. 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:
KB/t
kilobytes per transfer
tps
transfers per second
MB/s
megabytes per second
The standard iostat device display, with the -I flag specified, shows the following statistics:
KB/t
kilobytes per transfer
xfrs
total number of transfers
MB
total number of megabytes transferred
The old-style iostat display (using -o ) shows the following statistics:
sps
sectors transferred per second
tps
transfers per second
msps
average milliseconds per transaction
The old-style iostat display, with the -I flag specified, shows the following statistics:
blk
total blocks/sectors transferred
xfr
total transfers
msps
average milliseconds per transaction
cpu
us
% of cpu time in user mode
ni
% of cpu time in user mode running niced processes
