linux命令——iotop
查看CPU使用情況用top，查看I/O使用情況就需要iotop。這個命令是在kernel v2.6.20中添加，安裝的時候要注意內核的版本號。
iotop常用快捷鍵
1. 左右箭頭 --> 改變排序方式，默認是按IO排序
2. r --> 改變排序順序
3. o --> 只顯示有IO輸出的進程
4. p --> 進程/線程的顯示方式的切換
5. a --> 顯示累積使用量
6. q --> 退出
一、安裝
yum install iotop
二、man iotop
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 and CONFIG_TASK_IO_ACCOUNTING options need to be enabled in your Linux kernel
build configuration, these options depend on CONFIG_TASKSTATS.
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 press-
ing 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.
-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)
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.
