How to check disk read or write utilization

Question

I want to know disk read / write utilization especially, only read or write utilization or write utilization I tried using iostat but it shows entire utilization,

How to check only disk read or only write utilization (The progress is consist of read + write works)

Answer 1

Perhaps iotop is the right tool for you.

On the left you can see which process causes how much load and the hdparm test I ran in the session on the right is clearly shown there.

Answer 2

If you wish to get the result in a graphical format then go with munin monitoring tool http://munin-monitoring.org/ It provide graphical information about Disk IO per device, Disk latency per device, Disk utilization and Disk throughput.