The command iostat is a useful complement to vmstat.
Unfortunately, iostat is not found on as many Unix systems as
vmstat. As the name implies, iostat tells you the
status of input and output on your workstation, namely, how your hard
disks and I/O (tty) ports are performing. Like vmstat, the
arguments of iostat are the frequency of reporting and the
total time for all reports.
This report is for a workstation with three hard
disks, xd0, sd0, and sd1. The columns under tty
report the number of characters written in and out. The columns under
each disk report bps, the number of blocks written per
second to that disk; the number of transfers per second, tps; and the
time in milliseconds for an average seek from that disk, msps.
% iostat 1 5 Write a report every second for 5 seconds.
tty xd0 sd0 sd1 cpu
tin tout bps tps msps bps tps msps bps tps msps us ni sy id
0 16 13 2 10.4 4 1 0.0 2 0 0.0 3 0 5 92
0 77 0 0 0.0 0 0 0.0 123 23 0.0 1 0 28 71
0 77 0 0 0.0 0 0 0.0 132 22 0.0 1 0 32 67
0 79 0 0 0.0 0 0 0.0 150 37 0.0 3 0 38 59
0 78 1 1 9.5 0 0 0.0 127 32 0.0 4 0 30 66
You will notice that the cpu usage is reported on the extreme right. While the ``wait time'' is not available on the listing produced by this Sun system, the column ni reports the amount of time spent running low priority, that is, ``niced,'' programs.