iotop - simple top-like I/O monitor
iotop watches I/O usage information output by the Linux kernel (requires 2.6.20
or later) and displays a table of current I/O usage by processes or threads on
the system. At least the CONFIG_TASK_DELAY_ACCT, CONFIG_TASK_IO_ACCOUNTING,
CONFIG_TASKSTATS and CONFIG_VM_EVENT_COUNTERS options need to be enabled in
your Linux kernel build configuration.
iotop displays columns for the I/O bandwidth read and written by each
process/thread during the sampling period. It also displays the percentage of
time the thread/process spent while swapping in and while waiting on I/O. For
each process, its I/O priority (class/level) is shown.
In addition, the total I/O bandwidth read and written during the sampling period
is displayed at the top of the interface. Total DISK READ
values represent total read and write bandwidth between
processes and kernel threads on the one side and kernel block device subsystem
on the other. While Actual DISK READ
and Actual DISK WRITE
values represent corresponding bandwidths for actual disk I/O between kernel
block device subsystem and underlying hardware (HDD, SSD, etc.). Thus
values may not be equal at any given moment of
time due to data caching and I/O operations reordering that take place inside
Use the left and right arrows to change the sorting, r to reverse the sorting
order, o to toggle the --only option, p to toggle the --processes option, a to
toggle the --accumulated option, q to quit or i to change the priority of a
thread or a process' thread(s). Any other key will force a refresh.
- Show the version number and exit
- -h, --help
- Show usage information and exit
- -o, --only
- Only show processes or threads actually doing I/O, instead
of showing all processes or threads. This can be dynamically toggled by
- -b, --batch
- Turn on non-interactive mode. Useful for logging I/O usage
- -n NUM, --iter=NUM
- Set the number of iterations before quitting (never quit by
default). This is most useful in non-interactive mode.
- -d SEC, --delay=SEC
- Set the delay between iterations in seconds (1 second by
default). Accepts non-integer values such as 1.1 seconds.
- -p PID, --pid=PID
- A list of processes/threads to monitor (all by
- -u USER, --user=USER
- A list of users to monitor (all by default)
- -P, --processes
- Only show processes. Normally iotop shows all threads.
- -a, --accumulated
- Show accumulated I/O instead of bandwidth. In this mode,
iotop shows the amount of I/O processes have done since iotop
- -k, --kilobytes
- Use kilobytes instead of a human friendly unit. This mode
is useful when scripting the batch mode of iotop. Instead of choosing the
most appropriate unit iotop will display all sizes in kilobytes.
- -t, --time
- Add a timestamp on each line (implies --batch). Each line
will be prefixed by the current time.
- -q, --quiet
- suppress some lines of header (implies --batch). This
option can be specified up to three times to remove header lines.
- column names are only printed on the first iteration,
- column names are never printed,
- the I/O summary is never printed.
iotop was written by Guillaume Chazarain.
This manual page was started by Paul Wise for the Debian project and is placed
in the public domain.