iostat [-CUdKIoT?] [-c count]
[-n devs] [-w wait] [drives]
displays kernel I/O statistics on terminal, device and cpu operations.
The first statistics that are printed are averaged over the system uptime.
-c count Repeat count times.
| -w seconds wait seconds between each display. default 1.
| -C CPU statistics. default on, -d supresses.
| -U system load averages. default on, -d supresses.
| -T BSD TTY statistics. default, unless -d is specified.
| -d only device statistics. (i.e. supress -C -U)
| -I total for period, rather than
average per second
| -n n up to n of devices.
| -o old-style i.e. Sectors/second, transfers/second, and miliseconds/seek .
-I total blocks/sectors, total transfers, and miliseconds per seek.
-K block count in kilobytes rather then the block size.
| tty
tin characters read from terminals
tout characters written to terminals
|
devices
Device operations.
KB/t KiloBytes per transfer
tps Transfers per second
MB/s MegaBytes per second
-I shows:
KB/t KiloBytes per transfer
xfrs total number of transfers
MB total number of megabytes transferred
|
old-style -o shows:
sps sectors transferred per second
tps Transfers Per Second
msps average MilliSeconds Per transaction
old-style with -o -I shows:
blk total Blocks/sectors transferred
xfr total transfers
msps average MilliSeconds Per transaction
cpu us % of cpu time in user mode;
sy system mode; id idle mode
| | | | | | | | | | | |
EXAMPLES
Display statistics for the first disk device every second ad infinitum.
/usr/sbin/iostat -w 1 disk0
KB/t tps MB/s
5.04 75 0.37
0.00 0 0.00
8.00 4 0.03
13.56 16 0.21
4.39 433 1.85
4.01 4074 15.95
4.00 4156 16.25
4.01 3907 15.29
4.09 1681 6.71
(This part can be supressed by using -d)
cpu load average comments by Ed
us sy id 1m 5m 15m
4 2 89 0.12 0.33 0.38 <-average
4 3 92 0.12 0.33 0.38 < quite
4 3 92 0.11 0.32 0.38 < quite
2 2 96 0.10 0.31 0.37 < Disk I/O starting
46 4 91 0.10 0.31 0.37 < continues; user 91 jumps the CPU
19 3 79 0.10 0.31 0.37 continues
21 1 78 0.10 0.31 0.37 continues
18 3 80 0.10 0.31 0.37
10 2 59 0.17 0.33 0.38 < CPU time picks up too
| |
for the devices 8 times, one second interval(default). First display is average to date.
/usr/sbin/iostat -c 8
total statistics every three seconds ad infinitum.
/usr/sbin/iostat -Iw 3
total statistics using the old-style 9 times, with a 2 second wait
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.
/usr/sbin/iostat -odICTw 2 -c 9
see: fstat(1), netstat(1),
nfsstat(1), ps(1), pstat(8)
The sections starting with Interpreting system activity in Installing and Operating 4.3BSD.
BSD September 27, 2001