mrtg
The Multi Router Traffic Grapher (MRTG) is a tool to monitor the traffic load on network links. MRTG generates HTML pages containing PNG images which provide a LIVE visual representation of this traffic. Check http://www.stat.ee.ethz.ch/mrtg/ to see what it does.
Go to http://oss.oetiker.ch/mrtg for all the details about mrtg.
# 注释 ：MRTG 是一个监测网络链路流量的工具，生成 HTML 页面（内嵌 PNG 图片）
# 注释 ：MRTG 的亮点
MRTG works on most UNIX platforms and Windows NT.
# 注释：可移植性。MRTG 可以在 UNIX 和 WINDOWS 上运行
MRTG is written in Perl and comes with full source.
# 注释 ：MRTG 是用 Perl 写的，附带源代码
MRTG Uses a highly portable SNMP implementation written entirely in Perl (thanks to Simon Leinen). There is no need to install any external SNMP package.
# 注释 ：MRTG 使用自己写的可移植性强的 SNMP 客户端，不需要事先安装任何 SNMP 软件包
MRTG can read the new SNMPv2c 64bit counters. No more counter wrapping.
# 注释 ：MRTG 能够读取 SNMP v2c 的 64 bit 计数器。
Reliable Interface Identification
Router interfaces can be identified by IP address, description and ethernet address in addition to the normal interface number.
# 注释 ：MRTG 可以通过 ip地址、描述信息、MAC 地址来区分不同的物理接口
MRTG's logfiles do NOT grow thanks to the use of a unique data consolidation algorithm.
# 注释 ：由于 MRTG 采取了数据合并算法，所以日志大小固定。
MRTG comes with a set of configuration tools which make configuration and setup very simple.
# 注释 ：MRTG 通过提供一系列的工具实现自动配置
Time critical routines are written in C (thanks to the initiative of Dave Rand my Co-Author).
# 注释：重要的例程都是用 C 写的，保证了软件的性能
Graphics are generated directly in PNG format using the GD library by Thomas Boutell.
# 注释 ：图片是使用 GD 库生成的 PNG 格式。
The look of the webpages produced by MRTG is highly configurable.
# 注释 ：MRTG 生成的页面外观可以自由的修改
MRTG has built-in hooks for using RRDtool. If you are strapped for performance this may help.
# 注释 ：MRTG 内建支持 RRDtool
MRTG consists of a Perl script which uses SNMP to read the traffic counters of your routers and a fast C program which logs the traffic data and creates beautiful graphs representing the traffic on the monitored network connection. These graphs are embedded into webpages which can be viewed from any modern Web-browser.
# 注释 ：MRTG 使用一个 Perl 脚本，通过 SNMP 读取流量信息。并通过 C 程序快速记录流量数据日志和生成图表
In addition to a detailed daily view, MRTG also creates visual representations of the traffic seen during the last seven days, the last five weeks and the last twelve months. This is possible because MRTG keeps a log of all the data it has pulled from the router. This log is automatically consolidated so that it does not grow over time, but still contains all the relevant data for all the traffic seen over the last two years. This is all performed in an efficient manner. Therefore you can monitor 200 or more network links from any halfway decent UNIX box.
# 注释 ：MRTG 除了提供每天的流量图外，还能提供每周的、每5周、每年的图表。
# 但即使这样日志文件也不会太大。
MRTG is not limited to monitoring traffic, though. It is possible to monitor any SNMP variable you choose. You can even use an external program to gather the data which should be monitored via MRTG. People are using MRTG, to monitor things such as System Load, Login Sessions, Modem availability and more. MRTG even allows you to accumulate two or more data sources into a single graph.
# 注释 ：MRTG 不限于监测流量，任何 SNMP 对象都可以被监测。
# 甚至还可以使用外部程序来收集数据，再交给 MRTG 。例如监测系统负载、会话数量等等
In 1994 I was working at a site where we had one 64kbit line to the outside world. Obviously, everybody was interested in knowing how the link was performing. So I wrote a quick hack which created a constantly updated graph on the web that showed the traffic load on our Internet link. This eventually evolved into a rather configurable Perl script called MRTG-1.0 which I released in spring 1995. After a few updates, I left my job at DMU to start work at the Swiss Federal Institute of Technology. Due to lack of time I had to put MRTG aside. One day in January of 1996, I received email from Dave Rand asking if I had any ideas why MRTG was so slow. Actually, I did. MRTG's programming was not very efficient and it was written entirely in Perl. After a week or so, Dave wrote back to me and said he had tried what I had suggested for improving MRTG's speed. Since the changes did not help much, he had decided to rewrite the time-critical sections of MRTG in C. The code was attached to his email. His tool increased the speed of MRTG by a factor of 40! This got me out of my 'MRTG ignorance' and I started to spend my spare time developing of MRTG-2.
Soon after MRTG-2 development had begun I started to give beta copies to interested parties. In return I got many feature patches, a lot of user feedback and bug fixes. The product you are getting now wouldn't be in this state if it hadn't been for the great contributions and support I received from of many people. I would like to take this opportunity to thank them all. (See the files CHANGES for a long list of folk people who helped to make MRTG what it is today.)
Mrtg is also the name of the script you have to run to poll data and generate the graphs. Most configuration is set through the configuration file; some command-line options exist all the same.
# 注释 ：mrtg 也是用来轮询的脚本的名称，可以带下面的参数
--user username and --group groupname
Run as the given user and/or group. (Unix Only)
# 注释 ：--user <user> , --group <grp> 表示以什么用户/用户组运行
Use an alternate lock-file (the default is to use the configuration-file appended with _l).
# 注释 ：--lock-file <file> 指定锁文件。默认是配置文件名后面加上 "_l"
Use an alternate confcache-file (the default is to use the configuration-file appended with .ok)
# 注释 ：--confcache-file <file> 给出配置缓存文件。默认是配置文件加 ".ok"
If this is set to writable filename, all output from mrtg (warnings, debug messages, errors) will go to filename. If you are running on Win32 you can specify eventlog instead of a filename which will send all error to the windows event log.
NOTE:Note, there is no Message DLL for mrtg. This has the side effect that the windows event logger will display a nice message with every entry in the event log, complaing about the fact that mrtg has no message dll. If any of the Windows folks want to contribute one, they are welcome.
# 注释 ：--logging <file> |eventlog 设置 MRTG 的输出信息写到什么地方。如果是 <filename> ，则记录到文件。如果是 windows ，则 使用 "eventlog"
Put MRTG into the background, running as a daemon. This works the same way as the config file option, but the switch is required for proper FHS operation (because /var/run is writable only by root)
# 注释 ：--daemon 表示 MRTG 以守护进程方式运行
Configure all mrtg paths to conform to the FHS specification; http://www.pathname.com/fhs/
# 注释 ：--fhs 配置所有 MRTG 路径符合 FHS 规范
# 问题 ：什么是 FHS 规范？
Only check the cfg file for errors. Do not do anything.
# 注释 ：--check 仅仅检查配置文件的错误，其他的不做
# 可以使用该选项来检查配置文件的语法和格式是否正确
Define the name and path of the pid file for mrtg running as a daemon
# 注释 ：--pid-file=<string> 定义以 daemon 方式运行的 MRTG 的 pid 文件的路径
Only update the logfile, do not produce graphics or html pages
# 注释 ：--log-only 只更新日志，不生成图表或者 HTML 页面
Enable debug options. The argument of the debug option is a comma separated list of debug values:
cfg - watch the config file reading
dir - directory mangeling
base - basic program flow
tarp - target parser
snpo - snmp polling
fork - forking view
time - some timing info
log - logging of data via rateup or rrdtool
# 注释 ：--debug=<string> 启用 debug 功能，可选的 <string> 有如下几个 ：
# -）cfg ：输出 mrtg 读取配置文件的信息
# -）dir ：输出目录信息
# -）base ：输出基础程序的信息
# -）tarp ：输出目标解释的信息
# -）snpo ：输出 snmp 轮询的信息
# -）fork ：输出 fork view 的信息
# -）time ：输出定时信息
# -）log ：输出日志记录信息
# 注释 ：可以指定多个 token ，每个用 ',' 分开
Example:
--debug="cfg,snpo"
Learn more about MRTG by going to the mrtg home page on: http://oss.oetiker.ch/mrtg
Tobias Oetiker <tobi@oetiker.ch> and many contributors
Last Update: 09/06/06 by Tobias Oetiker
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