# sar -p -d -f /var/log/sa/saXX  | grep 'DEV\|root'

# iotop

# pidstat -dl 5

# for x in `seq 1 1 10`; do ps -eo state,pid,cmd | grep "^D"; echo "----"; sleep 5; done

http://bencane.com/2012/08/06/troubleshooting-high-io-wait-in-linux/