Unix Notes - iostat

iostat -x 5 100

                 extended device statistics
device    r/s    w/s   kr/s   kw/s wait actv  svc_t  %w  %b
md10      1.2   15.2    9.6   19.7  0.1  0.5   35.9   8   8
md11      0.6   15.2    4.8   19.7  0.0  0.5   29.9   0   7
md12      0.6   15.2    4.8   19.7  0.0  0.4   28.1   0   7
md20      0.0    0.0    0.0    0.0  0.0  0.0    0.0   0   0
md21      0.0    0.0    0.0    0.0  0.0  0.0    0.0   0   0