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IOTOP(8)                    System Manager's Manual                   IOTOP(8)
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   CON-
       FIG_TASK_DELAY_ACCT,  CONFIG_TASK_IO_ACCOUNTING,  CONFIG_TASKSTATS  and
       CONFIG_VM_EVENT_COUNTERS  options need to be enabled in your Linux ker-
       nel  build  configuration  and  since  Linux  kernel  5.14,  the   ker-
       nel.task_delayacct sysctl enabled.
       iotop  displays  columns for the I/O bandwidth read and written by each
       process/thread during the sampling period. It also  displays  the  per-
       centage  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 sam-
       pling period is displayed at the top of the interface.  Total DISK READ
       and  Total  DISK  WRITE 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 Total and Actual values may not be equal at any given
       moment  of  time due to data caching and I/O operations reordering that
       take place inside Linux kernel.
       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 --pro-
       cesses 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 tog-
              gled 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-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 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 choos-
              ing 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(8)