Linux iotop工具简介

Linux iotop工具简介
iotop的简介:

iotop是一款开源、免费的用来监控磁盘I/O使用状况的类似top命令的工具,iotop可以监控进程的I/O信息。它是Python语言编写的,与iostat工具比较,iostat是系统级别的IO监控,而iotop是进程级别IO监控。目前最新的版本为iotop 0.6。其官方网址http://guichaz.free.fr/iotop/

iotop的安装:

注意,iotop的安装有前提条件(如果操作系统不满足这些条件,iotop无法正确安装):

1:内核版本为2.6.20或更高版本

2:Python 2.7或更高的版本

官方文档的详细介绍如下:

Linux has always been able to show how much I/O was going on (the bi and bo columns of the vmstat 1 command).

Iotop is a Python program with a top like UI used to show of behalf of which process is the I/O going on. It requires Python ≥ 2.7 and a Linux kernel ≥ 2.6.20 with the TASK_DELAY_ACCT CONFIG_TASKSTATS, TASK_IO_ACCOUNTING and CONFIG_VM_EVENT_COUNTERS options on.

iotop的yum安装

yum安装是最简单、快捷的。前提条件是你有配置yum的源配置。

[root@DB-Server ~]# python -V
Python 2.7.5
[root@DB-Server ~]# uname -a
Linux DB-Server 3.10.0-862.el7.x86_64 #1 SMP Fri Apr 20 16:44:24 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
[root@DB-Server ~]#

[root@DB-Server ~]# yum -y install iotop

iotop的源码安装

wget http://guichaz.free.fr/iotop/files/iotop-0.6.tar.bz2
tar -xvf iotop-0.6.tar.gz
cd iotop-0.6
python setup.py build
python setup.py install

iotop的参数

iotop --help

Usage: /usr/local/sbin/iotop [OPTIONS]

DISK READ and DISK WRITE are the block I/O bandwidth used during the sampling

  1. SWAPIN and IO are the percentages of time the thread spent respectively
  2. swapping in and waiting on I/O more generally. PRIO is the I/O priority at

which the thread is running (set using the ionice command).

Controls: left and right arrows to change the sorting column, r to invert the
sorting order, o to toggle the --only option, p to toggle the --processes
option, a to toggle the --accumulated option, i to change I/O priority, q to
quit, any other key to force a refresh.

Options:
--version show program's version number and exit
-h, --help show this help message and exit
-o, --only only show processes or threads actually doing I/O
-b, --batch non-interactive mode
-n NUM, --iter=NUM number of iterations before ending [infinite]
-d SEC, --delay=SEC delay between iterations [1 second]
-p PID, --pid=PID processes/threads to monitor [all]
-u USER, --user=USER users to monitor [all]
-P, --processes only show processes, not all threads
-a, --accumulated show accumulated I/O instead of bandwidth
-k, --kilobytes use kilobytes instead of a human friendly unit
-t, --time add a timestamp on each line (implies --batch)
-q, --quiet suppress some lines of header (implies --batch)

参数

长参数

参数描述

--version

显示版本号

-h

--help

显示帮助信息

-o

--only

只显示正在产生I/O的进程或线程,运行过程中,可以通过按o随时切换

-b

--batch

非交互模式下运行,一般用来记录日志。

-n NUM

--iter=NUM

设置监控(显示)NUM次,主要用于非交互模式。默认无限

-d SEC

--delay=SEC

设置显示的间隔秒数,支持非整数

-p PID

--pid=PID

只显示指定进程(PID)的信息

-u USER

--user=USER

显示指定的用户的进程的信息

-P

--processes

只显示进程,不显示所有线程

-a

--accumulated

累积的I/O,显示从iotop启动后每个进程累积的I/O总数,便于诊断问题

-k

--kilobytes

显示使用KB单位

-t

--time

非交互模式下,加上时间戳。

-q

--quiet

只在第一次监测时显示列名. 去除头部一些行:这个参数可以设置最多3次来移除头部行:-q列头部只在最初交互显示一次;-qq列头部不显示;-qqq,I/O的总结不显示

iotop的快捷键

r:反向排序,

o:切换至选项--only,

p:切换至--processes选项,

a:切换至--accumulated选项

q:退出

i:改变线程的优先级

iotop的例子

1:只显示正在产生I/O的进程

iotop -o

clip_image001

2:使用非交互模式将iotop命令输出信息写入日志

nohup iotop -b -o -n 10 -d 5 -t > /tmp/iotop.log &

3:借助iotop命令找到消耗I/O最高的进程,然后通过进程找到其正在执行的SQL语句

iotop -oP

PID PRIO USER DISK READ DISK WRITE SWAPIN IO> COMMAND

11741 be/4 oracle 4.70 M/s 0.00 B/s 0.00 % 98.60 % ora_s004_SCM2

11739 be/4 oracle 66.99 M/s 0.00 B/s 0.00 % 93.30 % ora_s005_SCM2

11741 be/4 oracle 21.76 M/s 0.00 B/s 0.00 % 91.78 % ora_s006_SCM2

11743 be/4 oracle 4.87 M/s 3.78 M/s 0.00 % 27.74 % ora_s007_SCM2

11745 be/4 oracle 62.39 K/s 0.00 B/s 0.00 % 2.88 % ora_s008_SCM2

11733 be/4 oracle 39.00 K/s 0.00 B/s 0.00 % 2.08 % ora_s002_SCM2

11697 be/4 oracle 0.00 B/s 1879.61 K/s 0.00 % 0.30 % ora_dbw0_SCM2

11699 be/4 oracle 0.00 B/s 102.36 K/s 0.00 % 0.20 % ora_lgwr_SCM2

在找到消耗I/O最大的进程后,找出ORACLE进程正在执行的SQL语句

SQL> @getsql_by_spid.sql

Enter value for pid: 11741

old 13: WHERE c.spid = '&pid'))

new 13: WHERE c.spid = '11741'))

SQL_TEXT


...............................(实际环境中,这里会输出SQL语句)

getsql_by_spid.sql脚本如下所示:

SELECT /+ ORDERED /

     sql_text
FROM v$sqltext a

WHERE (a.hash_value, a.address) IN (

        SELECT DECODE (sql_hash_value,
                       0, prev_hash_value,
                       sql_hash_value
                      ),
               DECODE (sql_hash_value, 0, prev_sql_addr, sql_address)
          FROM v$session b
         WHERE b.paddr = (SELECT addr
                            FROM v$process c
                           WHERE c.spid = '&pid'))

ORDER BY piece ASC
/

这里只简单列了几个例子,因为iotop命令非常简单,了解iotop的参数和快捷方式后,基本上只需根据实际需求去获取进程或信息的I/O信息,剩下就是分析判断了。

作者:潇湘隐者
出处:http://www.cnblogs.com/kerrycode/

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