System Monitor
gives me a graphical display of Network data flow.
Is there something similar for the data flow on the local file-system itself?
iostat -m
shows the I/O per device that has been caused since system startup.
You can combine it with watch 'iostat -m'
iostat
and NightwishFan's iotop
work well together in a split Terminal window (the broad picture, and the detail).
There is a System Monitor gnome-panel applet that shows a tiny graph of IO. Also you can use the program iotop, which is like top/htop in the console though for I/O.
iotop
works well enough (for me), but my kernal isn't compiled suitably to allow it to output some of its features... CONFIG_TASK_DELAY_ACCT not enabled in kernel, cannot determine SWAPIN and IO %
... I don't know what they are, so it doesn't much matter.. :)