Article submitted by Paul Wise. DebADay needs you more than ever! Please submit good articles about software you like!
iotop is a console application for monitoring the I/O usage of processes on your system. It is especially handy for answering the question “Grrr, sloooowness, why is my disk churning so much?”
Just type iotop in your terminal and you will get a regularly updated list of processes and the amount of I/O they are currently using: reads and writesin bytes per second, and percentage of time spent swapping and waiting for I/O.
iotop is related to top and vmstat. In top you see a display of CPU and memory usage but not I/O. The vmstat utility shows it, but its just a stream of one-line reports instead of a dynamic display and doesn’t show the information in a per-process way.
Note that iotop needs the CONFIG_TASK_DELAY_ACCT and CONFIG_TASK_IO_ACCOUNTING options enabled in the kernel; in Debian stock kernels, that’s already the case.