1MRTG(1) mrtg MRTG(1)
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6 mrtg - What is MRTG ?
7
9 The Multi Router Traffic Grapher (MRTG) is a tool to monitor the
10 traffic load on network links. MRTG generates HTML pages containing
11 PNG images which provide a LIVE visual representation of this traffic.
12 Check http://www.stat.ee.ethz.ch/mrtg/ to see what it does.
13 Go to
15 http://oss.oetiker.ch/mrtg for all the details about mrtg.
16
18 Portable
19 MRTG works on most UNIX platforms and Windows NT.
20 Perl
22 MRTG is written in Perl and comes with full source.
23 Portable SNMP
25 MRTG Uses a highly portable SNMP implementation written entirely in
26 Perl (thanks to Simon Leinen). There is no need to install any
27 external SNMP package.
28 SNMPv2c support
30 MRTG can read the new SNMPv2c 64bit counters. No more counter
31 wrapping.
32 Reliable Interface Identification
34 Router interfaces can be identified by IP address, description and
35 ethernet address in addition to the normal interface number.
36 Constant size Logfiles
38 MRTG's logfiles do NOT grow thanks to the use of a unique data
39 consolidation algorithm.
40 Automatic Configuration
42 MRTG comes with a set of configuration tools which make
43 configuration and setup very simple.
44 Performance
46 Time critical routines are written in C (thanks to the initiative
47 of Dave Rand my Co-Author).
48 GIF free Graphics
50 Graphics are generated directly in PNG format using the GD library
51 by Thomas Boutell.
52 Customizability
54 The look of the webpages produced by MRTG is highly configurable.
55 RRDtool
57 MRTG has built-in hooks for using RRDtool. If you are strapped for
58 performance this may help.
59
61 MRTG consists of a Perl script which uses SNMP to read the traffic
62 counters of your routers and a fast C program which logs the traffic
63 data and creates beautiful graphs representing the traffic on the
64 monitored network connection. These graphs are embedded into webpages
65 which can be viewed from any modern Web-browser.
66 In addition to a detailed daily view, MRTG also creates visual
68 representations of the traffic seen during the last seven days, the
69 last five weeks and the last twelve months. This is possible because
70 MRTG keeps a log of all the data it has pulled from the router. This
71 log is automatically consolidated so that it does not grow over time,
72 but still contains all the relevant data for all the traffic seen over
73 the last two years. This is all performed in an efficient manner.
74 Therefore you can monitor 200 or more network links from any halfway
75 decent UNIX box.
76 MRTG is not limited to monitoring traffic, though. It is possible to
78 monitor any SNMP variable you choose. You can even use an external
79 program to gather the data which should be monitored via MRTG. People
80 are using MRTG, to monitor things such as System Load, Login Sessions,
81 Modem availability and more. MRTG even allows you to accumulate two or
82 more data sources into a single graph.
83
85 In 1994 I was working at a site where we had one 64kbit line to the
86 outside world. Obviously, everybody was interested in knowing how the
87 link was performing. So I wrote a quick hack which created a constantly
88 updated graph on the web that showed the traffic load on our Internet
89 link. This eventually evolved into a rather configurable Perl script
90 called MRTG-1.0 which I released in spring 1995. After a few updates, I
91 left my job at DMU to start work at the Swiss Federal Institute of
92 Technology. Due to lack of time I had to put MRTG aside. One day in
93 January of 1996, I received email from Dave Rand asking if I had any
94 ideas why MRTG was so slow. Actually, I did. MRTG's programming was not
95 very efficient and it was written entirely in Perl. After a week or so,
96 Dave wrote back to me and said he had tried what I had suggested for
97 improving MRTG's speed. Since the changes did not help much, he had
98 decided to rewrite the time-critical sections of MRTG in C. The code
99 was attached to his email. His tool increased the speed of MRTG by a
100 factor of 40! This got me out of my 'MRTG ignorance' and I started to
101 spend my spare time developing of MRTG-2.
102 Soon after MRTG-2 development had begun I started to give beta copies
104 to interested parties. In return I got many feature patches, a lot of
105 user feedback and bug fixes. The product you are getting now wouldn't
106 be in this state if it hadn't been for the great contributions and
107 support I received from of many people. I would like to take this
108 opportunity to thank them all. (See the files CHANGES for a long list
109 of folk people who helped to make MRTG what it is today.)
110
112 Mrtg is also the name of the script you have to run to poll data and
113 generate the graphs. Most configuration is set through the
114 configuration file; some command-line options exist all the same.
115 --user username and --group groupname
117 Run as the given user and/or group. (Unix Only)
118 --lock-file filename
120 Use an alternate lock-file (the default is to use the
121 configuration-file appended with "_l").
122 --confcache-file filename
124 Use an alternate confcache-file (the default is to use the
125 configuration-file appended with ".ok")
126 --logging filename|eventlog
128 If this is set to writable filename, all output from mrtg
129 (warnings, debug messages, errors) will go to filename. If you are
130 running on Win32 you can specify eventlog instead of a filename
131 which will send all error to the windows event log.
132 NOTE:Note, there is no Message DLL for mrtg. This has the side
134 effect that the windows event logger will display a nice message
135 with every entry in the event log, complaing about the fact that
136 mrtg has no message dll. If any of the Windows folks want to
137 contribute one, they are welcome.
138 --daemon
140 Put MRTG into the background, running as a daemon. This works the
141 same way as the config file option, but the switch is required for
142 proper FHS operation (because /var/run is writable only by root)
143 --fhs
145 Configure all mrtg paths to conform to the FHS specification;
146 http://www.pathname.com/fhs/
147 --check
149 Only check the cfg file for errors. Do not do anything.
150 --pid-file=s
152 Define the name and path of the pid file for mrtg running as a
153 daemon
154 --log-only
156 Only update the logfile, do not produce graphics or html pages
157 --debug=s
159 Enable debug options. The argument of the debug option is a comma
160 separated list of debug values:
161 cfg - watch the config file reading
163 dir - directory mangeling
164 base - basic program flow
165 tarp - target parser
166 snpo - snmp polling
167 fork - forking view
168 time - some timing info
169 log - logging of data via rateup or rrdtool
170 Example:
172 --debug="cfg,snpo"
174
176 Learn more about MRTG by going to the mrtg home page on:
177 http://oss.oetiker.ch/mrtg
178
180 Tobias Oetiker <tobi@oetiker.ch> and many contributors
1812.17.4 2012-01-12 MRTG(1)