In the event that you need to monitor disk IO in Linux, you can do so in various ways. With most Linux distributions, these commands are helpful for this :

# Interactively sortable list of processes' current/instantaneous disk I/O, on ten second update interval. Use the arrow keys to switch the sort column :
iotop   --processes   --only   --delay=10

# Similar to the above, but using the total I/O done while monitoring instead of the current value. Update rate here is five seconds :
iotop   --processes   --only   --delay=5    --accumulated

# List all disk devices with their current read/write rates in megabytes :
iostat   -d  -m

# Periodically list each device and its I/O rates in megabytes, ignoring those with no activity :
iostat   -d  -m  -t  -y  -z    10