iostat - Reports I/O statistics
iostat [drive...] [interval] [count]
Forces iostat to display specific drives. If drive is not
specified (or the specified drive does not exist on the
system or cluster, iostat displays the first two drives
(even if more than two disk drives are configured in the
system). Causes iostat to report once each interval seconds.
The first report is for all time since the system
was last booted, and each subsequent report is for the
last interval only.The value must not be 0. Specifies the
number of reports. For example, iostat 1 10 would produce
10 reports at 1-second intervals. You cannot specify
count without interval because the first numeric argument
to iostat is assumed to be interval.
The iostat command reports the following information: For
terminals (collectively), the number of characters read
and written per second. For each disk, the number of
transfers per second and bytes transferred per second (in
kilobytes). For the system, the percentage of time the
system has spent in user mode, in user mode running low
priority (nice) processes, in system mode, and idling.
To compute this information, iostat counts data transfer
completions, the number of words transferred for each
disk, and the collective number of input and output characters
for terminals. Also, each sixtieth of a second,
iostat examines the state of each disk and makes a tally
if the disk is active.
When you issue an iostat command on a cluster member, it
displays statistics only for those disks that are local to
the member and that member's usage of those shared disks
that it has mounted. It displays 0 for other disks in
the cluster (those it doesn't have mounted), regardless of
whether they are on the shared bus or are local to some
other member.
The output from this example displays cpu, terminal, and
disk statistics for the first two disks on the system providing
5 reports at 1 second intervals:
# iostat 1 5
tty floppy1 dsk9 cpu
tin tout bps tps bps tps us ni sy id
0 3 0 0 0 0 1 0 4 95
4 58 0 0 0 0 1 0 2 97
1 53 0 0 0 0 0 0 2 98
5 59 0 0 0 0 1 0 1 98
6 60 0 0 0 0 1 0 2 97
The second example specifies device names in the command:
# iostat dsk2 dsk3 cdrom2
tty dsk2 cdrom2 dsk3 cpu
tin tout bps tps bps tps bps tps us ni sy id
0 13 11 5 5 2 2427 1213 0 1 1 98
Commands: vmstat(1)
iostat(1)
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