1IOTOP(8)                    System Manager's Manual                   IOTOP(8)
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NAME

6       iotop - simple top-like I/O monitor
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SYNOPSIS

9       iotop [OPTIONS]
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DESCRIPTION

12       iotop  watches  I/O  usage  information output by the Linux kernel (re‐
13       quires 2.6.20 or later) and displays a table of current  I/O  usage  by
14       processes  or  threads  on  the  system.  At  least the CONFIG_TASK_DE‐
15       LAY_ACCT,   CONFIG_TASK_IO_ACCOUNTING,   CONFIG_TASKSTATS   and    CON‐
16       FIG_VM_EVENT_COUNTERS  options  need to be enabled in your Linux kernel
17       build configuration and since Linux kernel 5.14, the kernel.task_delay‐
18       acct sysctl enabled.
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20       iotop  displays  columns for the I/O bandwidth read and written by each
21       process/thread during the sampling period. It also  displays  the  per‐
22       centage  of  time  the thread/process spent while swapping in and while
23       waiting on I/O. For each process, its  I/O  priority  (class/level)  is
24       shown.
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26       In  addition,  the total I/O bandwidth read and written during the sam‐
27       pling period is displayed at the top of the interface.  Total DISK READ
28       and  Total  DISK  WRITE values represent total read and write bandwidth
29       between processes and kernel threads on the one side and  kernel  block
30       device subsystem on the other. While Current DISK READ and Current DISK
31       WRITE values represent corresponding bandwidths for  current  disk  I/O
32       between  kernel  block  device  subsystem and underlying hardware (HDD,
33       SSD, etc.).  Thus Total and Current values may  not  be  equal  at  any
34       given  moment of time due to data caching and I/O operations reordering
35       that take place inside Linux kernel.
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37       Use the left and right arrows to change the sorting, r to  reverse  the
38       sorting  order,  o  to toggle the --only option, p to toggle the --pro‐
39       cesses option, a to toggle the --accumulated option, q to quit or i  to
40       change the priority of a thread or a process's thread(s). Any other key
41       will force a refresh.
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OPTIONS

44       --version
45              Show the version number and exit
46
47       -h, --help
48              Show usage information and exit
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50       -o, --only
51              Only show processes or threads actually doing  I/O,  instead  of
52              showing  all  processes or threads. This can be dynamically tog‐
53              gled by pressing o.
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55       -b, --batch
56              Turn on non-interactive mode.  Useful for logging I/O usage over
57              time.
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59       -n NUM, --iter=NUM
60              Set  the number of iterations before quitting (never quit by de‐
61              fault).  This is most useful in non-interactive mode.
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63       -d SEC, --delay=SEC
64              Set the delay between iterations in seconds  (1  second  by  de‐
65              fault).  Accepts non-integer values such as 1.1 seconds.
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67       -p PID, --pid=PID
68              A list of processes/threads to monitor (all by default).
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70       -u USER, --user=USER
71              A list of users to monitor (all by default)
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73       -P, --processes
74              Only show processes. Normally iotop shows all threads.
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76       -a, --accumulated
77              Show  accumulated  I/O instead of bandwidth. In this mode, iotop
78              shows the amount of I/O processes have done since iotop started.
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80       -k, --kilobytes
81              Use kilobytes instead of a human friendly  unit.  This  mode  is
82              useful when scripting the batch mode of iotop. Instead of choos‐
83              ing the most appropriate unit iotop will display  all  sizes  in
84              kilobytes.
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86       -t, --time
87              Add  a  timestamp on each line (implies --batch). Each line will
88              be prefixed by the current time.
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90       -q, --quiet
91              suppress some lines of header (implies --batch). This option can
92              be specified up to three times to remove header lines.
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94       --no-help
95              Suppress the keyboard shortcuts help display.
96              -q     column names are only printed on the first iteration,
97              -qq    column names are never printed,
98              -qqq   the I/O summary is never printed.
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SEE ALSO

101       ionice(1), top(1), vmstat(1), atop(1), htop(1)
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AUTHOR

104       iotop was written by Guillaume Chazarain.
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106       This manual page was started by Paul Wise for the Debian project and is
107       placed in the public domain.
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111                                  April 2009                          IOTOP(8)
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