《Ourlinux》杂志

nmon for Linux 官方：http://nmon.sourceforge.net/pmwiki.php

下面是收集的资料：nmon工具介绍 (监控优化-操作系统监控)

Posted by Bhavin Turakhia

In my neverending quest of performance monitoring, I have been constantly trying to find better ways to monitor disk utilization on a server. At Directi we use the usual medley of tools at our disposal viz. iostat, sar, sysstat. I made serious progress last week, when Dushyanth from my team shared this post on IO Monitoring on Linux, by the folks over at Pythian, on our internal mailing list. Here are my notes on the subject.

Performance measurement and Capacity planning are a science. It is common practice at Directi to attempt to determine what the performance bottlenecks in any given application are. A usual generalization is to determine whether an application is cpu-bound / memory-bound / IO bound.

IO bound applications end up wasting cpu cycles, especially incase of Disk IO, since most programming languages do not have Async Disk IO support today. Therefore in order to maximize performance and optimize resource utilization one should try and reduce iowait time of a CPU and tweak a deployment to make an application cpu-bound.

When your CPU seems to be spending a lot of time on iowait you need to make some changes. However an iowait can occur either because there is a lot of Disk/Network IO taking place, or because the disk subsystem is saturated and cannot provide greater throughput. iostat allows you to determine which one it is. A regular iostat output consists of the following fields -

# iostat -dkx 60

Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util
dm-0 0.00 0.00 611.40 414.23 20286.60 1656.93 42.79 17.50 17.33 0.96 98.57

Explanation of the above fields:

* Device: the block device whose performance counters are being reported
* r/s and w/s: number of read and write requests issued per second to the device (in this case 611 and 414)
* rsec/s and wsec/s – number of sectors read/written per second
* rkB/s and wkB/s – number of kilobytes read/written per second
* avgrq-sz – average number of sectors per request (for both reads and writes). ie (rsec + wsec) / (r + w)
* avgqu-sz – average queue length in the monitoring interval (in this case 42.79)
* await – average time that each IO Request took to complete. This includes the time that the request was waiting in the queue and the time that the request took to be serviced by the device
* svctim – average time each IO request took to complete during the monitoring interval
* Note: await includes svctim. Infact await (average time taken for each IO Request to complete) = the average time that each request was in queue (lets call it queuetime) PLUS the average time each request took to process (svctim)
* %util: This number depicts the percentage of time that the device spent in servicing requests. This can be calculated with the above values. In the above example the total number of reads and writes issued per second is 611 + 414 => 1025. Each request takes 0.96 ms to process. Therefore 1025 requests would take 1025 x 0.96 => 984 ms to process. So out of the 1 second that these requests were sent to the device in, 984 ms were taken to process the requests. This means the device utilization is 984/1000 * 100 => ~98.4%. As you can see in the above iostat output the %util does show ~ 98.5%

Interpreting iostat values

Lets take the above example

Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util
dm-0 0.00 0.00 611.40 414.23 20286.60 1656.93 42.79 17.50 17.33 0.96 98.57

* avg time that each request spent in queue (qtime) = await – svctime = 17.33 – 0.96 => 16.37 ms
* avg time tha each request spent being serviced = 0.96 ms
* so averagely each IO request spent 17.33ms to et processed of which 16.37 ms were spent just waiting in queue
* %util can be calculated as (r/s + w/s) * svctim / 1000ms * 100 => 1025*0.96/1000 * 100 => 98.5%
* This simple means that in a 1 second interval, 1025 requests were sent to disk, each of which took 0.96ms for the disk to process resulting in 984 ms of disk utilization time in a period of 1 s (or 1000 ms). This means the disk is greater than 98% utilized

On this disk subsystem, it is clear that the disk cannot process more IO requests than what it is getting

Lets take another example -

Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util
sdb 6.33 139.07 46.30 19.53 526.27 634.40 35.26 0.54 8.17 3.30 21.74

* avg time that each request spent in queue (qtime) = await – svctime = 8.17 – 3.30 => 4.87 ms
* avg time tha each request spent being serviced = 3.30 ms
* so averagely each IO request spent 8.17 ms to et processed of which 4.87 ms (a little more than half) were spent waiting in queue
* %util can be calculated as (r/s + w/s) * svctim / 1000ms * 100 => 65.83 * 3.3/1000 * 100 => 21.72%
* This simple means that in a 1 second interval, 65 requests were sent to disk, each of which took 3.30ms for the disk to process resulting in 217 ms of disk utilization time in a period of 1 s (or 1000 ms). This means the disk is around 21.7 % utilized

On this disk subsystem, it is clear that the disk is not fully utilized. While due to the nature of the requests, averagely requests are spending half their time in queue, that is not so bad. This disk subsystem is capable of greater throughput.

Notes

On every Linux box the following should be graphed at 5 minute averages

* %util: When this figure is consistently approaching above 80% you will need to take any of the following actions -
o increasing RAM so dependence on disk reduces
o increasing RAID controller cache so disk dependence decreases
o increasing number of disks so disk throughput increases (more spindles working parallely)
o horizontal partitioning
* (await-svctim)/await*100: The percentage of time that IO operations spent waiting in queue in comparison to actually being serviced. If this figure goes above 50% then each IO request is spending more time waiting in queue than being processed. If this ratio skews heavily upwards (in the >75% range) you know that your disk subsystem is not being able to keep up with the IO requests and most IO requests are spending a lot of time waiting in queue. In this scenario you will again need to take any of the actions above
* %iowait: This number shows the % of time the CPU is wasting in waiting for IO. A part of this number can result from network IO, which can be avoided by using an Async IO library. The rest of it is simply an indication of how IO-bound your application is. You can reduce this number by ensuring that disk IO operations take less time, more data is available in RAM, increasing disk throughput by increasing number of disks in a RAID array, using SSD (Check my post on Solid State drives vs Hard Drives) for portions of the data or all of the data etc

From：http://bhavin.directi.com/iostat-and-disk-utilization-monitoring-nirvana/

下个手机客户端，然后注册个pushme.to的帐号，比如：ourlinux，然后就可以通过pushme的接口进行发消息了。

HTML代码如下：

linux下简单的执行如下：

curl -o /dev/null -d “nickname=ourlinux&signature=OWL&submit=%20OK%20&&message=test” http://pushme.to/ourlinux/

记得将ourlinux改成自己的接收的账号！

这样就可以将报警的信息通过pushme来发送了！

其他的不说了，很简单，一看就明白了！

感谢joe推荐使用pushme！

From：http://article.yeeyan.org/view/54517/91367

翻译：litfresh | 2010-02-24 16:24:59 | 阅读2097 | 来源

作为一个软件开发者，你一定会对网络应用如何工作有一个完整的层次化的认知，同样这里也包括这些应用所用到的技术：像浏览器，HTTP，HTML，网络服务器，需求处理等等。

本文将更深入的研究当你输入一个网址的时候，后台到底发生了一件件什么样的事～

1. 首先嘛，你得在浏览器里输入要网址:

2. 浏览器查找域名的IP地址

导航的第一步是通过访问的域名找出其IP地址。DNS查找过程如下：

DNS递归查找如下图所示：

3. 浏览器给web服务器发送一个HTTP请求

因为像Facebook主页这样的动态页面，打开后在浏览器缓存中很快甚至马上就会过期，毫无疑问他们不能从中读取。

所以，浏览器将把一下请求发送到Facebook所在的服务器：

GET http://facebook.com/ HTTP/1.1
 Accept: application/x-ms-application, image/jpeg, application/xaml+xml, [...]
 User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; [...]
 Accept-Encoding: gzip, deflate
 Connection: Keep-Alive
 Host: facebook.com
 Cookie: datr=1265876274-[...]; locale=en_US; lsd=WW[...]; c_user=2101[...]

GET 这个请求定义了要读取的URL： “http://facebook.com/”。 浏览器自身定义 (User-Agent 头)， 和它希望接受什么类型的相应 (Accept and Accept-Encoding 头). Connection头要求服务器为了后边的请求不要关闭TCP连接。

请求中也包含浏览器存储的该域名的cookies。可能你已经知道，在不同页面请求当中，cookies是与跟踪一个网站状态相匹配的键值。这样cookies会存储登录用户名，服务器分配的密码和一些用户设置等。Cookies会以文本文档形式存储在客户机里，每次请求时发送给服务器。

除了获取请求，还有一种是发送请求，它常在提交表单用到。发送请求通过URL传递其参数(e.g.: http://robozzle.com/puzzle.aspx?id=85)。发送请求在请求正文头之后发送其参数。

像“http://facebook.com/”中的斜杠是至关重要的。这种情况下，浏览器能安全的添加斜杠。而像“http://example.com/folderOrFile”这样的地址，因为浏览器不清楚folderOrFile到底是文件夹还是文件，所以不能自动添加斜杠。这时，浏览器就不加斜杠直接访问地址，服务器会响应一个重定向，结果造成一次不必要的握手。

4. facebook服务的永久重定向响应

图中所示为Facebook服务器发回给浏览器的响应：

HTTP/1.1 301 Moved Permanently
 Cache-Control: private, no-store, no-cache, must-revalidate, post-check=0,
 pre-check=0
 Expires: Sat, 01 Jan 2000 00:00:00 GMT
 Location: http://www.facebook.com/
 P3P: CP="DSP LAW"
 Pragma: no-cache
 Set-Cookie: made_write_conn=deleted; expires=Thu, 12-Feb-2009 05:09:50 GMT;
 path=/; domain=.facebook.com; httponly
 Content-Type: text/html; charset=utf-8
 X-Cnection: close
 Date: Fri, 12 Feb 2010 05:09:51 GMT
 Content-Length: 0

服务器给浏览器响应一个301永久重定向响应，这样浏览器就会访问“http://www.facebook.com/” 而非“http://facebook.com/”。

5. 浏览器跟踪重定向地址

现在，浏览器知道了“http://www.facebook.com/”才是要访问的正确地址，所以它会发送另一个获取请求：

GET http://www.facebook.com/ HTTP/1.1
 Accept: application/x-ms-application, image/jpeg, application/xaml+xml, [...]
 Accept-Language: en-US
 User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; [...]
 Accept-Encoding: gzip, deflate
 Connection: Keep-Alive
 Cookie: lsd=XW[...]; c_user=21[...]; x-referer=[...]
 Host: www.facebook.com

头信息以之前请求中的意义相同。

6. 服务器“处理”请求

服务器接收到获取请求，然后处理并返回一个响应。

这表面上看起来是一个顺向的任务，但其实这中间发生了很多有意思的东西- 就像作者博客这样简单的网站，何况像facebook那样访问量大的网站呢！

• Web 服务器软件
  web服务器软件（像IIS和阿帕奇）接收到HTTP请求，然后确定执行什么请求处理来处理它。请求处理就是一个能够读懂请求并且能生成HTML来进行响应的程序（像ASP.NET,PHP,RUBY…）。举个最简单的例子，需求处理可以以映射网站地址结构的文件层次存储。像http://example.com/folder1/page1.aspx这个地址会映射/httpdocs/folder1/page1.aspx这个文件。web服务器软件可以设置成为地址人工的对应请求处理，这样page1.aspx的发布地址就可以是http://example.com/folder1/page1。
• 请求处理
  请求处理阅读请求及它的参数和cookies。它会读取也可能更新一些数据，并讲数据存储在服务器上。然后，需求处理会生成一个HTML响应。

7. 服务器发回一个HTML响应

图中为服务器生成并返回的响应：

HTTP/1.1 200 OK
 Cache-Control: private, no-store, no-cache, must-revalidate, post-check=0,
 pre-check=0
 Expires: Sat, 01 Jan 2000 00:00:00 GMT
 P3P: CP="DSP LAW"
 Pragma: no-cache
 Content-Encoding: gzip
 Content-Type: text/html; charset=utf-8
 X-Cnection: close
 Transfer-Encoding: chunked
 Date: Fri, 12 Feb 2010 09:05:55 GMT

 2b3��������T�n�@����[...]

整个响应大小为35kB，其中大部分在整理后以blob类型传输。

内容编码头告诉浏览器整个响应体用gzip算法进行压缩。解压blob块后，你可以看到如下期望的HTML：

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"   
 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
 <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"
 lang="en" id="facebook" class=" no_js">
 <head>
 <meta http-equiv="Content-type" content="text/html; charset=utf-8" />
 <meta http-equiv="Content-language" content="en" />
 ...

关于压缩，头信息说明了是否缓存这个页面，如果缓存的话如何去做，有什么cookies要去设置（前面这个响应里没有这点）和隐私信息等等。

8. 浏览器开始显示HTML

在浏览器没有完整接受全部HTML文档时，它就已经开始显示这个页面了：

9. 浏览器发送获取嵌入在HTML中的对象

在浏览器显示HTML时，它会注意到需要获取其他地址内容的标签。这时，浏览器会发送一个获取请求来重新获得这些文件。

下面是几个我们访问facebook.com时需要重获取的几个URL：

• 图片
  http://static.ak.fbcdn.net/rsrc.php/z12E0/hash/8q2anwu7.gif
  http://static.ak.fbcdn.net/rsrc.php/zBS5C/hash/7hwy7at6.gif
  …
• CSS 式样表
  http://static.ak.fbcdn.net/rsrc.php/z448Z/hash/2plh8s4n.css
  http://static.ak.fbcdn.net/rsrc.php/zANE1/hash/cvtutcee.css
  …
• JavaScript 文件
  http://static.ak.fbcdn.net/rsrc.php/zEMOA/hash/c8yzb6ub.js
  http://static.ak.fbcdn.net/rsrc.php/z6R9L/hash/cq2lgbs8.js
  …

这些地址都要经历一个和HTML读取类似的过程。所以浏览器会在DNS中查找这些域名，发送请求，重定向等等…

但不像动态页面那样，静态文件会允许浏览器对其进行缓存。有的文件可能会不需要与服务器通讯，而从缓存中直接读取。服务器的响应中包含了静态文件保存的期限信息，所以浏览器知道要把它们缓存多长时间。还有，每个响应都可能包含像版本号一样工作的ETag头（被请求变量的实体值），如果浏览器观察到文件的版本ETag信息已经存在，就马上停止这个文件的传输。

10. 浏览器发送异步（AJAX）请求

在Web 2.0伟大精神的指引下，页面显示完成后客户端仍与服务器端保持着联系。

以Facebook聊天功能为例，它会持续与服务器保持联系来及时更新你那些亮亮灰灰的好友状态。为了更新这些头像亮着的好友状态，在浏览器中执行的JavaScript代码会给服务器发送异步请求。这个异步请求发送给特定的地址，它是一个按照程式构造的获取或发送请求。还是在Facebook这个例子中，客户端发送给http://www.facebook.com/ajax/chat/buddy_list.php一个发布请求来获取你好友里哪个在线的状态信息。

提起这个模式，就必须要讲讲”AJAX”– “异步JavaScript 和 XML”，虽然服务器为什么用XML格式来进行响应也没有个一清二白的原因。再举个例子吧，对于异步请求，Facebook会返回一些JavaScript的代码片段。

总结一下

希望看了本文，你能明白不同的网络模块是如何协同工作的

原文：http://www.cyberciti.biz/tips/top-linux-monitoring-tools.html
by VIVEK GITE

Need to monitor Linux server performance? Try these built-in command and a few add-on tools. Most Linux distributions are equipped with tons of monitoring. These tools provide metrics which can be used to get information about system activities. You can use these tools to find the possible causes of a performance problem. The commands discussed below are some of the most basic commands when it comes to system analysis and debugging server issues such as:

1. Finding out bottlenecks.
2. Disk (storage) bottlenecks.
3. CPU and memory bottlenecks.
4. Network bottlenecks.

#1: top - Process Activity Command

The top program provides a dynamic real-time view of a running system i.e. actual process activity. By default, it displays the most CPU-intensive tasks running on the server and updates the list every five seconds.

Commonly Used Hot Keys

The top command provides several useful hot keys:

Hot Key	Usage
t	Displays summary information off and on.
m	Displays memory information off and on.
A	Sorts the display by top consumers of various system resources. Useful for quick identification of performance-hungry tasks on a system.
f	Enters an interactive configuration screen for top. Helpful for setting up top for a specific task.
o	Enables you to interactively select the ordering within top.
r	Issues renice command.
k	Issues kill command.
z	Turn on or off color/mono

=> Related: How do I Find Out Linux CPU Utilization?

#2: vmstat - System Activity, Hardware and System Information

The command vmstat reports information about processes, memory, paging, block IO, traps, and cpu activity.
# vmstat 3
Sample Outputs:

procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu------
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
 0  0      0 2540988 522188 5130400    0    0     2    32    4    2  4  1 96  0  0
 1  0      0 2540988 522188 5130400    0    0     0   720 1199  665  1  0 99  0  0
 0  0      0 2540956 522188 5130400    0    0     0     0 1151 1569  4  1 95  0  0
 0  0      0 2540956 522188 5130500    0    0     0     6 1117  439  1  0 99  0  0
 0  0      0 2540940 522188 5130512    0    0     0   536 1189  932  1  0 98  0  0
 0  0      0 2538444 522188 5130588    0    0     0     0 1187 1417  4  1 96  0  0
 0  0      0 2490060 522188 5130640    0    0     0    18 1253 1123  5  1 94  0  0

Display Memory Utilization Slabinfo

# vmstat -m

Get Information About Active / Inactive Memory Pages

# vmstat -a
=> Related: How do I find out Linux Resource utilization to detect system bottlenecks?

#3: w - Find Out Who Is Logged on And What They Are Doing

w command displays information about the users currently on the machine, and their processes.
# w username
# w vivek
Sample Outputs:

 17:58:47 up 5 days, 20:28,  2 users,  load average: 0.36, 0.26, 0.24
USER     TTY      FROM              LOGIN@   IDLE   JCPU   PCPU WHAT
root     pts/0    10.1.3.145       14:55    5.00s  0.04s  0.02s vim /etc/resolv.conf
root     pts/1    10.1.3.145       17:43    0.00s  0.03s  0.00s w

#4: uptime - Tell How Long The System Has Been Running

The uptime command can be used to see how long the server has been running. The current time, how long the system has been running, how many users are currently logged on, and the system load averages for the past 1, 5, and 15 minutes.
# uptime
Output:

 18:02:41 up 41 days, 23:42,  1 user,  load average: 0.00, 0.00, 0.00

1 can be considered as optimal load value. The load can change from system to system. For a single CPU system 1 - 3 and SMP systems 6-10 load value might be acceptable.

#5: ps - Displays The Processes

ps command will report a snapshot of the current processes. To select all processes use the -A or -e option:
# ps -A
Sample Outputs:

  PID TTY          TIME CMD
    1 ?        00:00:02 init
    2 ?        00:00:02 migration/0
    3 ?        00:00:01 ksoftirqd/0
    4 ?        00:00:00 watchdog/0
    5 ?        00:00:00 migration/1
    6 ?        00:00:15 ksoftirqd/1
....
.....
 4881 ?        00:53:28 java
 4885 tty1     00:00:00 mingetty
 4886 tty2     00:00:00 mingetty
 4887 tty3     00:00:00 mingetty
 4888 tty4     00:00:00 mingetty
 4891 tty5     00:00:00 mingetty
 4892 tty6     00:00:00 mingetty
 4893 ttyS1    00:00:00 agetty
12853 ?        00:00:00 cifsoplockd
12854 ?        00:00:00 cifsdnotifyd
14231 ?        00:10:34 lighttpd
14232 ?        00:00:00 php-cgi
54981 pts/0    00:00:00 vim
55465 ?        00:00:00 php-cgi
55546 ?        00:00:00 bind9-snmp-stat
55704 pts/1    00:00:00 ps

ps is just like top but provides more information.

Show Long Format Output

# ps -Al
To turn on extra full mode (it will show command line arguments passed to process):
# ps -AlF

To See Threads ( LWP and NLWP)

# ps -AlFH

To See Threads After Processes

# ps -AlLm

Print All Process On The Server

# ps ax
# ps axu

Print A Process Tree

# ps -ejH
# ps axjf
# pstree

Print Security Information

# ps -eo euser,ruser,suser,fuser,f,comm,label
# ps axZ
# ps -eM

See Every Process Running As User Vivek

# ps -U vivek -u vivek u

Set Output In a User-Defined Format

# ps -eo pid,tid,class,rtprio,ni,pri,psr,pcpu,stat,wchan:14,comm
# ps axo stat,euid,ruid,tty,tpgid,sess,pgrp,ppid,pid,pcpu,comm
# ps -eopid,tt,user,fname,tmout,f,wchan

Display Only The Process IDs of Lighttpd

# ps -C lighttpd -o pid=
OR
# pgrep lighttpd
OR
# pgrep -u vivek php-cgi

Display The Name of PID 55977

# ps -p 55977 -o comm=

Find Out The Top 10 Memory Consuming Process

# ps -auxf | sort -nr -k 4 | head -10

Find Out top 10 CPU Consuming Process

# ps -auxf | sort -nr -k 3 | head -10

#6: free - Memory Usage

The command free displays the total amount of free and used physical and swap memory in the system, as well as the buffers used by the kernel.
# free
Sample Output:

            total       used       free     shared    buffers     cached
Mem:      12302896    9739664    2563232          0     523124    5154740
-/+ buffers/cache:    4061800    8241096
Swap:      1052248          0    1052248

=> Related: :

1. Linux Find Out Virtual Memory PAGESIZE
2. Linux Limit CPU Usage Per Process
3. How much RAM does my Ubuntu / Fedora Linux desktop PC have?

#7: iostat - Average CPU Load, Disk Activity

The command iostat report Central Processing Unit (CPU) statistics and input/output statistics for devices, partitions and network filesystems (NFS).
# iostat
Sample Outputs:

Linux 2.6.18-128.1.14.el5 (www03.nixcraft.in) 	06/26/2009

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           3.50    0.09    0.51    0.03    0.00   95.86

Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn
sda              22.04        31.88       512.03   16193351  260102868
sda1              0.00         0.00         0.00       2166        180
sda2             22.04        31.87       512.03   16189010  260102688
sda3              0.00         0.00         0.00       1615          0

=> Related: : Linux Track NFS Directory / Disk I/O Stats

#8: sar - Collect and Report System Activity

The sar command is used to collect, report, and save system activity information. To see network counter, enter:
# sar -n DEV | more
To display the network counters from the 24th:
# sar -n DEV -f /var/log/sa/sa24 | more
You can also display real time usage using sar:
# sar 4 5
Sample Outputs:

Linux 2.6.18-128.1.14.el5 (www03.nixcraft.in) 		06/26/2009

06:45:12 PM       CPU     %user     %nice   %system   %iowait    %steal     %idle
06:45:16 PM       all      2.00      0.00      0.22      0.00      0.00     97.78
06:45:20 PM       all      2.07      0.00      0.38      0.03      0.00     97.52
06:45:24 PM       all      0.94      0.00      0.28      0.00      0.00     98.78
06:45:28 PM       all      1.56      0.00      0.22      0.00      0.00     98.22
06:45:32 PM       all      3.53      0.00      0.25      0.03      0.00     96.19
Average:          all      2.02      0.00      0.27      0.01      0.00     97.70

=> Related: : How to collect Linux system utilization data into a file

#9: mpstat - Multiprocessor Usage

The mpstat command displays activities for each available processor, processor 0 being the first one. mpstat -P ALL to display average CPU utilization per processor:
# mpstat -P ALL
Sample Output:

Linux 2.6.18-128.1.14.el5 (www03.nixcraft.in)	 	06/26/2009

06:48:11 PM  CPU   %user   %nice    %sys %iowait    %irq   %soft  %steal   %idle    intr/s
06:48:11 PM  all    3.50    0.09    0.34    0.03    0.01    0.17    0.00   95.86   1218.04
06:48:11 PM    0    3.44    0.08    0.31    0.02    0.00    0.12    0.00   96.04   1000.31
06:48:11 PM    1    3.10    0.08    0.32    0.09    0.02    0.11    0.00   96.28     34.93
06:48:11 PM    2    4.16    0.11    0.36    0.02    0.00    0.11    0.00   95.25      0.00
06:48:11 PM    3    3.77    0.11    0.38    0.03    0.01    0.24    0.00   95.46     44.80
06:48:11 PM    4    2.96    0.07    0.29    0.04    0.02    0.10    0.00   96.52     25.91
06:48:11 PM    5    3.26    0.08    0.28    0.03    0.01    0.10    0.00   96.23     14.98
06:48:11 PM    6    4.00    0.10    0.34    0.01    0.00    0.13    0.00   95.42      3.75
06:48:11 PM    7    3.30    0.11    0.39    0.03    0.01    0.46    0.00   95.69     76.89

=> Related: : Linux display each multiple SMP CPU processors utilization individually.

#10: pmap - Process Memory Usage

The command pmap report memory map of a process. Use this command to find out causes of memory bottlenecks.
# pmap -d PID
To display process memory information for pid # 47394, enter:
# pmap -d 47394
Sample Outputs:

47394:   /usr/bin/php-cgi
Address           Kbytes Mode  Offset           Device    Mapping
0000000000400000    2584 r-x-- 0000000000000000 008:00002 php-cgi
0000000000886000     140 rw--- 0000000000286000 008:00002 php-cgi
00000000008a9000      52 rw--- 00000000008a9000 000:00000   [ anon ]
0000000000aa8000      76 rw--- 00000000002a8000 008:00002 php-cgi
000000000f678000    1980 rw--- 000000000f678000 000:00000   [ anon ]
000000314a600000     112 r-x-- 0000000000000000 008:00002 ld-2.5.so
000000314a81b000       4 r---- 000000000001b000 008:00002 ld-2.5.so
000000314a81c000       4 rw--- 000000000001c000 008:00002 ld-2.5.so
000000314aa00000    1328 r-x-- 0000000000000000 008:00002 libc-2.5.so
000000314ab4c000    2048 ----- 000000000014c000 008:00002 libc-2.5.so
.....
......
..
00002af8d48fd000       4 rw--- 0000000000006000 008:00002 xsl.so
00002af8d490c000      40 r-x-- 0000000000000000 008:00002 libnss_files-2.5.so
00002af8d4916000    2044 ----- 000000000000a000 008:00002 libnss_files-2.5.so
00002af8d4b15000       4 r---- 0000000000009000 008:00002 libnss_files-2.5.so
00002af8d4b16000       4 rw--- 000000000000a000 008:00002 libnss_files-2.5.so
00002af8d4b17000  768000 rw-s- 0000000000000000 000:00009 zero (deleted)
00007fffc95fe000      84 rw--- 00007ffffffea000 000:00000   [ stack ]
ffffffffff600000    8192 ----- 0000000000000000 000:00000   [ anon ]
mapped: 933712K    writeable/private: 4304K    shared: 768000K

The last line is very important:

• mapped: 933712K total amount of memory mapped to files
• writeable/private: 4304K the amount of private address space
• shared: 768000K the amount of address space this process is sharing with others

=> Related: : Linux find the memory used by a program / process using pmap command

#11 and #12: netstat and ss - Network Statistics

The command netstat displays network connections, routing tables, interface statistics, masquerade connections, and multicast memberships. ss command is used to dump socket statistics. It allows showing information similar to netstat. See the following resources about ss and netstat commands:

• ss: Display Linux TCP / UDP Network and Socket Information
• Get Detailed Information About Particular IP address Connections Using netstat Command

#13: iptraf - Real-time Network Statistics

The iptraf command is interactive colorful IP LAN monitor. It is an ncurses-based IP LAN monitor that generates various network statistics including TCP info, UDP counts, ICMP and OSPF information, Ethernet load info, node stats, IP checksum errors, and others. It can provide the following info in easy to read format:

• Network traffic statistics by TCP connection
• IP traffic statistics by network interface
• Network traffic statistics by protocol
• Network traffic statistics by TCP/UDP port and by packet size
• Network traffic statistics by Layer2 address

#14: tcpdump - Detailed Network Traffic Analysis

The tcpdump is simple command that dump traffic on a network. However, you need good understanding of TCP/IP protocol to utilize this tool. For.e.g to display traffic info about DNS, enter:
# tcpdump -i eth1 'udp port 53'
To display all IPv4 HTTP packets to and from port 80, i.e. print only packets that contain data, not, for example, SYN and FIN packets and ACK-only packets, enter:
# tcpdump 'tcp port 80 and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0)’
To display all FTP session to 202.54.1.5, enter:
# tcpdump -i eth1 'dst 202.54.1.5 and (port 21 or 20'
To display all HTTP session to 192.168.1.5:
# tcpdump -ni eth0 'dst 192.168.1.5 and tcp and port http'
Use wireshark to view detailed information about files, enter:
# tcpdump -n -i eth1 -s 0 -w output.txt src or dst port 80

#15: strace - System Calls

Trace system calls and signals. This is useful for debugging webserver and other server problems. See how to use to trace the process and see What it is doing.

#16: /Proc file system - Various Kernel Statistics

/proc file system provides detailed information about various hardware devices and other Linux kernel information. See Linux kernel /proc documentations for further details. Common /proc examples:
# cat /proc/cpuinfo
# cat /proc/meminfo
# cat /proc/zoneinfo
# cat /proc/mounts

17#: Nagios - Server And Network Monitoring

Nagios is a popular open source computer system and network monitoring application software. You can easily monitor all your hosts, network equipment and services. It can send alert when things go wrong and again when they get better. FAN is “Fully Automated Nagios”. FAN goals are to provide a Nagios installation including most tools provided by the Nagios Community. FAN provides a CDRom image in the standard ISO format, making it easy to easilly install a Nagios server. Added to this, a wide bunch of tools are including to the distribution, in order to improve the user experience around Nagios.

18#: Cacti - Web-based Monitoring Tool

Cacti is a complete network graphing solution designed to harness the power of RRDTool’s data storage and graphing functionality. Cacti provides a fast poller, advanced graph templating, multiple data acquisition methods, and user management features out of the box. All of this is wrapped in an intuitive, easy to use interface that makes sense for LAN-sized installations up to complex networks with hundreds of devices. It can provide data about network, CPU, memory, logged in users, Apache, DNS servers and much more. See how to install and configure Cacti network graphing tool under CentOS / RHEL.

#19: KDE System Guard - Real-time Systems Reporting and Graphing

KSysguard is a network enabled task and system monitor application for KDE desktop. This tool can be run over ssh session. It provides lots of features such as a client/server architecture that enables monitoring of local and remote hosts. The graphical front end uses so-called sensors to retrieve the information it displays. A sensor can return simple values or more complex information like tables. For each type of information, one or more displays are provided. Displays are organized in worksheets that can be saved and loaded independently from each other. So, KSysguard is not only a simple task manager but also a very powerful tool to control large server farms.

See the KSysguard handbook for detailed usage.

#20: Gnome System Monitor - Real-time Systems Reporting and Graphing

The System Monitor application enables you to display basic system information and monitor system processes, usage of system resources, and file systems. You can also use System Monitor to modify the behavior of your system. Although not as powerful as the KDE System Guard, it provides the basic information which may be useful for new users:

• Displays various basic information about the computer’s hardware and software.
• Linux Kernel version
• GNOME version
• Hardware
• Installed memory
• Processors and speeds
• System Status
• Currently available disk space
• Processes
• Memory and swap space
• Network usage
• File Systems
• Lists all mounted filesystems along with basic information about each.

Bounce: Additional Tools

A few more tools:

• nmap - scan your server for open ports.
• lsof - list open files, network connections and much more.
• ntop web based tool - ntop is the best tool to see network usage in a way similar to what top command does for processes i.e. it is network traffic monitoring software. You can see network status, protocol wise distribution of traffic for UDP, TCP, DNS, HTTP and other protocols.
• Conky - Another good monitoring tool for the X Window System. It is highly configurable and is able to monitor many system variables including the status of the CPU, memory, swap space, disk storage, temperatures, processes, network interfaces, battery power, system messages, e-mail inboxes etc.
• GKrellM - It can be used to monitor the status of CPUs, main memory, hard disks, network interfaces, local and remote mailboxes, and many other things.
• vnstat - vnStat is a console-based network traffic monitor. It keeps a log of hourly, daily and monthly network traffic for the selected interface(s).
• htop - htop is an enhanced version of top, the interactive process viewer, which can display the list of processes in a tree form.
• mtr - mtr combines the functionality of the traceroute and ping programs in a single network diagnostic tool.

Did I miss something? Please add your favorite system motoring tool in the comments.

作者:tonnyom
原载: http://www.sanotes.net/html/y2010/449.html
版权所有。转载时必须以链接形式注明作者和原始出处及本声明。
From The Art of Scalability: Scalable Web Architecture, Processes, and Organizations for the Modern Enterprise
1, 单纯认为架构可扩展性只是个技术问题
2, 调用同步处理的过度使用
3, 一个问题还没处理完毕,就开始了新的架构调整
4, 没有合理的使用数据库
5, 架构被越扩展越复杂
6, 只依赖于垂直可伸缩性,单纯地考虑硬件方面的扩容
7, 从不吸取经验教训
8, 不断的改变开发策略,简单而重复的解决问题
9, 没有及时的使用缓存,或者使用的不够
10,过分依赖于第三方,这方面可能是指基础架构的非独立性,没有针对自己业务的应用层开发等等

作者:tonnyom
原载: http://www.sanotes.net/html/y2010/445.html
版权所有。转载时必须以链接形式注明作者和原始出处及本声明。
VirtualBox On FreeBSD 8.0 HOWTO
Author:
===========================================================
Tonnyom < at > gmail.com http://tonnyom.blogspot.com
版权声明:可以任意转载,转载时请务必以文字形式标明文章原始出处和作者信息及本声明.
INTRODUCTION:
===========================================================
VirtualBox 是一款功能强大的虚拟机软件,它不仅具有丰富的特色,而且性能也很优异.
同时VirtualBox 也是开源世界中的一员.
FreeBSD 是一种先进的操作系统，它支持 x86 兼容(包括 Pentium 和 Athlon )、amd64
兼容(包括 Opteron、Athlon64 和 EM64T)、 ARM、IA-64、PC-98以及 UltraSPARC架构
的计算机.FreeBSD 源于 BSD 美国加州大学伯克利分校开发 UNIX 版本,它由来自世界各
地的志愿者开发和维护.
PLATFORM:
===========================================================
FreeBSD 8.0-release amd64
virtualbox-ose-3.1.2 \\ /usr/ports/emulators/virtualbox-ose
virtualbox-ose-kmod-3.1.2 \\ /usr/ports/emulators/virtualbox-ose-kmod
PURPOSE:
===========================================================
建立一个类似于KVM on Linux的VirtualBox on FreeBSD虚拟化平台.
建立一个HostOS 为FreeBSD 环境,GuestOS 为Windows Linux Unix等OS环境
同时本文尽量采取操作简单化,命令行式的部署过程.宜于快速的进行虚拟环境的在线使用.
对于GuestOS 为FreeBSD本身的虚拟化方案,我个人还是推荐建议使用FreeBSD+Jail.
以后有机会可以介绍这块的内容.
FreeBSD 环境初始化+X-Server 安装及配置
===========================================================
#pkg_add -rv cvsup-without-gui
#vi /etc/make.conf
SUP= /usr/bin/csup
SUPFLAGS= -g -L 2
SUPHOST= cvsup.freebsdchina.org
SUPFILE= /usr/share/examples/cvsup/standard-supfile
PORTSSUPFILE= /usr/share/examples/cvsup/ports-supfile
DOCSUPFILE= /usr/share/examples/cvsup/doc-supfile
#cd /usr/src
#make update \\ 同步升级src ports docs
#pkg_add -rv xorg
#pkg_add -rv rgb
#cd /usr/X11R6/lib/X11/
#cp -Rpf rgb.txt rgb
VNC 安装以及配置
===========================================================
#pkg_add -rv vnc
#vi /usr/local/bin/vncserver
$cmd .= ” -co /usr/X11R6/lib/X11/rgb”;
#vncserver \\ 启动vnc server
注:
***关闭VNC Server
#vncserver -kill (you-hostname):1
VirtualBox 安装以及配置
===========================================================
#cd virtualbox-ose-3.1.2
#make install clean
#vi/boot/loader.conf \\ vboxdrv kernel module
vboxdrv_load=”YES”
#vi /etc/rc.conf \\ bridged networking
vboxnet_enable=”YES”
#reboot \\ 重启系统,加载所需模块
#pw groupmod vboxusers -m root \\ 加入root用户到vboxusers组(可选项)
远程客户机(Windows):
运行 vnc-4_1_3-x86_win32_viewer.exe
输入: you-vncserver-ip:5901
进入xterm 窗口,依次输入以下命令:
***创建虚拟机,生成XML 文件
/usr/local/bin/VBoxManage createvm –name WinXP -register
***创建虚拟机所需的磁盘空间
/usr/local/bin/VBoxManage createhd –filename WinXP.vdi –size 10000 –variant Fixed
***创建虚拟机所需的存储控制器以及虚拟CD/DVD 设备
/usr/local/bin/VBoxManage storagectl WinXP –name “IDE Controller” –add ide –controller PIIX4
注:
–add 可选项:
ide/sata/scsi/floppy
–controller 可选项:
LsiLogic/BusLogic/IntelAhci/PIIX3/PIIX4/ICH6/I82078
***添加磁盘设备到虚拟机
/usr/local/bin/VBoxManage storageattach WinXP –storagectl “IDE Controller” –port 0 –device 0 –type hdd –medium WinXP.vdi
***挂载需要安装系统的ISO 文件
/usr/local/bin/VBoxManage storageattach WinXP –storagectl “IDE Controller” –port 0 –device 1 –type dvddrive –medium /data/iso/xp_pro_with_sp3.iso
注:
–medium 可选项(iso 文件):
Windows (NT 4.0, 2000, XP, Server 2003, Vista, Windows 7), DOS/Windows 3.x, Linux (2.4 and 2.6), Solaris and OpenSolaris, and OpenBSD(来自官方介绍)
***配置虚拟机网卡(桥接模式):
/usr/local/bin/VBoxManage modifyvm WinXP –nic1 bridged –cableconnected1 on –bridgeadapter1 bce1
***启动虚拟机:
/usr/local/bin/VBoxManage startvm WinXP
===========================================================
Known Issues
===========================================================
VirtualBox 有2个版本,一个开源版,一个是商业版.
现移植到FreeBSD 8.0的VirtualBox已经是最新版本,也是目前运行最稳定的一个版本,但
还是缺失USB 设备的虚拟化支持,期待下个版本吧. ^_^
===========================================================
Reference
===========================================================
http://www.virtualbox.org/
http://wiki.freebsd.org/VirtualBox
http://www.realvnc.com/products/free/4.1/winvnc.html
http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/virtualization-host.html
===========================================================
Special Thx Joe@51.com for idea. and all buddy from JIBA QQ Group.Enjoy 2010!
===========================================================
TXT 下载
http://www.sanotes.net/wp-content/uploads/VirtualBox%20On%20FreeBSD%208.0%20HOWTO.txt

lsof 工具可列出某个Unix 进程所打开文件信息的清单,被打开文件的类型可能包括了:本地文件,目录,网络共享文件,块设备文件,字符设备文件,共享库,管道,软链接,套接字等等.

以下是具体的lsof 操作实例总结:

1,列出所有被打开文件信息

#lsof

2,查看某个被打开文件信息

#lsof /path/to/file
#lsof /path/to/file1 /path/to/file2

3,列出某个目录下的被打开文件

#lsof +D /path
#lsof | grep “/path”

4,列出某个用户下的被打开文件

#lsof -u nobody
#lsof -u nobody,root

5,列出某个进程下的被打开文件

#lsof -c httpd
#lsof -c httpd -c mysqld

6,复合查询(OR)被打开文件信息

#lsof -u nobody -c httpd

7,复合查询(AND)被打开文件信息

#lsof -a -u root -c httpd

8,查看除root之外所有用户的被打开文件

#lsof -u ^root

9,查看具体进程PID的被打开文件

#lsof -p 10101
#lsof -p 10101,10102,10103

10,列出所有网络连接

#lsof -i

11,列出所有网络TCP或者UDP连接

#lsof -i tcp
#lsof -i udp

12,查看具体网络端口信息

#lsof -i :80
#lsof -i tcp:80
#lsof -i udp:53

13,查看具体用户下所有网络连接

#lsof -a -u www -i

14,列出NFS 文件

#lsof -N

15,列出Unix 套接字文件

#lsof -U

16,列出某个特定文件描述符相关联的文件

#lsof -d 2
#lsof -d 0-2
#lsof -d mem

0 1 2 => FD: standard input, output, and error

17,列出所有网络连接关联的PID

#lsof -t -i

#kill -9 `lsof -t -i`  => kill all process use network

18,重复lsof 输出

#lsof -r 1 -a -u www -i

from: http://feedproxy.google.com/~r/blogspot/HpnK/~3/v-rLmhbiVmA/lsof.html

How to install VPN on CentOS 4/5 in 3 minites.

By pctechnic

cd /tmp

wget http://poptop.sourceforge.net/yum/stable/packages/dkms-2.0.17.5-1.noarch.rpm

wget http://poptop.sourceforge.net/yum/stable/packages/kernel_ppp_mppe-1.0.2-3dkms.noarch.rpm

If u use centos 4

wget http://poptop.sourceforge.net/yum/stable/packages/ppp-2.4.3-7.rhel4.i386.rpm

wget http://poptop.sourceforge.net/yum/stable/packages/pptpd-1.3.4-1.rhel4.i386.rpm

-

If u use centos 5

wget http://poptop.sourceforge.net/yum/stable/packages/ppp-2.4.4-3.1.rhel5.i386.rpm

wget http://poptop.sourceforge.net/yum/stable/packages/pptpd-1.3.4-1.rhel5.1.i386.rpm

-

rpm -ivh dkms-2.0.17.5-1.noarch.rpm

rpm -ivh kernel_ppp_mppe-1.0.2-3dkms.noarch.rpm

-

rpm -Uvh ppp-2.4.3-7.rhel4.i386.rpm

rpm -Uvh ppp-2.4.4-3.1.rhel5.i386.rpm

rpm -ivh pptpd-1.3.4-1.rhel4.i386.rpm

rpm -ivh pptpd-1.3.4-1.rhel5.1.i386.rpm

vi /etc/pptpd.conf

localip IP

remoteip 192.168.0.1-100

service pptpd start

service pptpd stop

vi /etc/ppp/chap-secrets

insert a new line

user servicename passwd IP

for example:

qa4pc pptpd bendy 192.168.10.20

VPN now can work.

but we have to set NAT IP forward

-

iptables -t nat -F

iptables -t nat -A POSTROUTING -s 192.168.10.0/24 -j SNAT –to 999.999.999.999

echo 1 >/proc/sys/net/ipv4/ip_forward

form: http://pctechnic.wordpress.com/2008/08/29/how-to-install-vpn-on-centos-45-in-3-minites/

网上其实有很多关于这方面的文章,那为什么还会有此篇呢,有这么几个原因,是我翻译的动力,

第一,概念和内容虽然老套,但都讲得很透彻,而且还很全面.

第二,理论结合实际,其中案例分析都不错.

第三,不花哨,采用的工具及命令都是最基本的,有助于实际操作.

但本人才疏学浅,译文大多数都是立足于自己对原文的理解,大家也可以自己去OSCAN上找原文,如果有什么较大出入,还望留言回复,甚是感激!

编者注：有什么问题可以联系本文译者Tonnyom[AT]hotmail.com 于2009.08.10翻译完毕，他的BLOG：http://tonnyom.yo2.cn或 http://www.sanotes.net

如果对本文编辑有什么问题和建议请联系我：bixuan@gmail.com http://www.ourlinux.net

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