1IOTOP(8) System Manager's Manual IOTOP(8)
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6 iotop - simple top-like I/O monitor
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9 iotop [OPTIONS]
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12 iotop watches I/O usage information output by the Linux kernel
13 (requires 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 CON‐
15 FIG_TASK_DELAY_ACCT, CONFIG_TASK_IO_ACCOUNTING, CONFIG_TASKSTATS and
16 CONFIG_VM_EVENT_COUNTERS options need to be enabled in your Linux ker‐
17 nel build configuration.
18 iotop displays columns for the I/O bandwidth read and written by each
20 process/thread during the sampling period. It also displays the per‐
21 centage of time the thread/process spent while swapping in and while
22 waiting on I/O. For each process, its I/O priority (class/level) is
23 shown.
24 In addition, the total I/O bandwidth read and written during the sam‐
26 pling period is displayed at the top of the interface. Total DISK READ
27 and Total DISK WRITE values represent total read and write bandwidth
28 between processes and kernel threads on the one side and kernel block
29 device subsystem on the other. While Actual DISK READ and Actual DISK
30 WRITE values represent corresponding bandwidths for actual disk I/O
31 between kernel block device subsystem and underlying hardware (HDD,
32 SSD, etc.). Thus Total and Actual values may not be equal at any given
33 moment of time due to data caching and I/O operations reordering that
34 take place inside Linux kernel.
35 Use the left and right arrows to change the sorting, r to reverse the
37 sorting order, o to toggle the --only option, p to toggle the --pro‐
38 cesses option, a to toggle the --accumulated option, q to quit or i to
39 change the priority of a thread or a process' thread(s). Any other key
40 will force a refresh.
41
43 --version
44 Show the version number and exit
45 -h, --help
47 Show usage information and exit
48 -o, --only
50 Only show processes or threads actually doing I/O, instead of
51 showing all processes or threads. This can be dynamically tog‐
52 gled by pressing o.
53 -b, --batch
55 Turn on non-interactive mode. Useful for logging I/O usage over
56 time.
57 -n NUM, --iter=NUM
59 Set the number of iterations before quitting (never quit by
60 default). This is most useful in non-interactive mode.
61 -d SEC, --delay=SEC
63 Set the delay between iterations in seconds (1 second by
64 default). Accepts non-integer values such as 1.1 seconds.
65 -p PID, --pid=PID
67 A list of processes/threads to monitor (all by default).
68 -u USER, --user=USER
70 A list of users to monitor (all by default)
71 -P, --processes
73 Only show processes. Normally iotop shows all threads.
74 -a, --accumulated
76 Show accumulated I/O instead of bandwidth. In this mode, iotop
77 shows the amount of I/O processes have done since iotop started.
78 -k, --kilobytes
80 Use kilobytes instead of a human friendly unit. This mode is
81 useful when scripting the batch mode of iotop. Instead of choos‐
82 ing the most appropriate unit iotop will display all sizes in
83 kilobytes.
84 -t, --time
86 Add a timestamp on each line (implies --batch). Each line will
87 be prefixed by the current time.
88 -q, --quiet
90 suppress some lines of header (implies --batch). This option can
91 be specified up to three times to remove header lines.
92 -q column names are only printed on the first iteration,
93 -qq column names are never printed,
94 -qqq the I/O summary is never printed.
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97 ionice(1), top(1), vmstat(1), atop(1), htop(1)
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100 iotop was written by Guillaume Chazarain.
101 This manual page was started by Paul Wise for the Debian project and is
103 placed in the public domain.
104 April 2009 IOTOP(8)