iostat
The iostat command returns information about I/O status. It lists statistics on current I/O activity for each disk device and system CPU utilization percentages. Here is a sample iostat output:
tty cpu
tin tout us ni sy id
1 18 19 0 3 78
/dev/*dsk/c0d*s*/dev/*dsk/cld*s*/dev/*dsk/c2d*s*/dev/*dsk/c4d*s*
bps sps msps bps sps msps bps sps msps bps sps msps
2 0.1 61.7 1 0.0 95.5 1 0.0 60.4 2 0.2 44.3
• The tin and tout display fields show the number of characters written to and from terminal devices.
• CPU information includes the % time spent in user mode (us), “niced” user mode (ni), system mode (sy), and idle (id).
• The disk I/O for each disk device shows the average number of blocks transferred per second (bps), average number of seeks per second (sps), and average time per seek in ms (msps).