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IOTOP(1)                                                              IOTOP(1)



NAME
       iotop - simple top-like I/O monitor

SYNOPSIS
       iotop [OPTIONS]

DESCRIPTION
       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,  CON-
       FIG_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.

       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.

OPTIONS
       --version
              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 pressing o.

       -b, --batch
              Turn on non-interactive mode.  Useful for logging I/O usage over time.

       -n NUM, --iter=NUM
              Set the number of iterations before quitting (never quit by default).  This is most useful in non-inter-
              active 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 default).

       -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 started.

       -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.
              -q     column names are only printed on the first iteration,
              -qq    column names are never printed,
              -qqq   the I/O summary is never printed.

SEE ALSO
       ionice(1), top(1), vmstat(1), atop(1), htop(1)

AUTHOR
       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.



                                  April 2009                          IOTOP(1)