分类： LINUX
2014-08-18 11:05:30
原文地址：MRTG 系列连载-3 ：参考指南（上篇） 作者：ailms
mrtg-reference
The runtime behaviour of MRTG is governed by a
configuration file. Run-of- ther-mill configuration files can be generated with
cfgmaker. (Check ). But for more elaborate configurations some hand-tuning is
required.
This document describes all the configuration options understood by the mrtg software.
# 注释 ：该文档描述了 MRTG 所知道的所有配置文件的选项
MRTG configuration file syntax follows some simple rules:
# 注释 ：MRTG 配置文件的语法有如下几个规则 ：
# -）第一是所有的 keyword 必须从行首开始
# -）如果一个行以空白（空格或者tab）开始，而上一行不是空白行，则被追加到上一行的行尾。这点和 sendmail.cf 的一样
# -）空行被忽略
# -）以 # 开头的行被认为是注释
# -）可以在配置文件中插入其他文件，就是使用 Include：指令
Include:
Example:
Include:
base-options.inc
If included files are specified with relative paths, both the current working directory and the directory containing the main config file will be searched for the files.
# 注释 ：如果 Include：给出的文件是相对路径的，则当前工作目录和存放主要配置文件的目录都会被搜索
# 注释 ：下面介绍全局性的关键字
WorkDir specifies where the logfiles and the
webpages should be created.
Example:
WorkDir:
/usr/tardis/pub/www/stats/mrtg
# 注释 ：首先是 WorkDir：选项
，这是必须的一个选项，表示 MRTG 的日志文件和 HTML 页面放在那里
# 注释 ：下面这些是可选的全局选项
HtmlDir specifies the directory where the html
(or shtml, but we'll get on to those later)
lives.
NOTE: Workdir overrides the settings for htmldir, imagedir and logdir.
Example:
Htmldir:
/www/mrtg/
# 注释 ：Hmtldir 表示 HTML 文件放在那里。
# 注意，WorkDir 将覆盖 Htmldir 、Imagedir、Logdir 这三个选项。
# 所以如果要指定其中一个，就需要三个单独定义
ImageDir specifies the directory where the
images live. They should be under the html
directory.
Example:
Imagedir:
/www/mrtg/images
# 注释 ：Imagedir 表示那里存放生成的图片。不过要注意，该目录必须是 HtmlDir 所指定的目录下的一个子目录
LogDir specifies the directory where the logs
are stored. This need not be under htmldir
directive.
Example:
Logdir:
/www/mrtg/logs
# 注释 ：Logdir 选项指定日志存放的目录，同样也必须是 Htmdir 所指定的目录的一个子目录
With system that supports fork (UNIX for
example), mrtg can fork itself into multiple instances while it is acquiring
data via snmp.
For situations with high latency or a great
number of devices this will speed things up considerably. It will not make
things faster, though, if you query a single switch sitting next
door.
As far as I know NT can not fork so this option
is not available on NT.
Example:
# 注释 ：Forks 选项是 UNIX 才有的。MRTG 可以在通过 SNMP 获取数据的同时 fork 出多个实例。
# 对于网络延迟较大或者需要轮询的设备数量众多的情况，该选项可以一定程度的减少所需要的时间
# forks：后面加上要 fork 的实例的数目
Forks:
4
When set to yes, IPv6 support is enabled if the
required libraries are present (see the manpage). When IPv6 is enabled, mrtg can talk to routers
using SNMP over IPv6 and targets may be specified by their numeric IPv6
addresses as well as by hostname or IPv4
address.
If IPv6 is enabled and the target is a hostname,
mrtg will try to resolve the hostname to an IPv6 address and, if this fails, to
an IPv4 address. Note that mrtg will only use IPv4 if you specify an IPv4
address or a hostname with no corresponding IPv6 address; it will not fall back
to IPv4 if it simply fails to communicate with the target using IPv6. This is by
design.
Note that many routers do not currently support
SNMP over IPv6. Use the IPv4Only per target option for these
routers.
IPv6 is disabled by
default.
Example:
EnableIPv6:
Yes
When set to yes, uses the Net::SNMP module
instead of the SNMP_SESSION module for generating snmp queries. This allows the
use of SNMPv3 if other snmpv3 parameters are
set.
SNMPv3 is disabled by
default.
Example:
EnableSnmpV3:
yes
How many seconds apart should the browser
(Netscape) be instructed to reload the page? If this is not defined, the default
is 300 seconds (5 minutes).
Example:
# 注释 ：Refresh 选项设置 MRTG 多长时间 reload 页面。也就是更新图表和日志。
# 默认是会议300秒，也就是5分钟
Refresh:
600
How often do you call mrtg? The default is 5
minutes. If you call it less often, you should specify it here. This does two
things:
# 注释： Interval 设置多长时间调用一次 MRTG 。默认也是5分钟，和 Refresh 一致。 这样可以做到及时更新。
# 该选项将会做两件事 ：
# -）生成的 HTML 页面将包括 Interval 的设置
# -）HTML 页面中的 META header 将会告诉 cache 多长时间更新一次
In this example, we tell mrtg that we will be
calling it every 10 minutes. If you are calling mrtg every 5 minutes, you can
leave this line commented out.
Example:
Interval:
10
Note that unless you are using rrdtool you can not set Interval to less than 5 minutes. If you are using rrdtool you can set interval down to 1 minute. Note though, setting the Interval for an rrdtool/mrtg setup will influence the initial creation of the database. If you change the interval later, all existing databases will remain at the resolution they were initially created with.
# 注释 ：注意，除非是使用 rrdtool ，否则 Interval 不能小于5分钟
# 如果使用 rrdtool ，可以调整为 1分钟
# 在安装 rrdtool/mrtg 时指定 Interval 会影响到数据库一开始的建立。
# 假如在后期改变了 Interval
，则原先的数据库仍然被保留
MRTG relies heavily on the real time clock of
your computer. If the time is set to a wrong value, especially if it is advanced
far into the future, this will cause mrtg to expire lots of supposedly old data
from the log files.
To prevent this, you can add a 'reasonability'
check by specifying a maximum age for log files. If a file seems to be older,
mrtg will not touch it but complain instead, giving you a chance to investigate
the cause.
Example:
# 问题 ：MaxAge 选项的作用是什么？
MaxAge:
7200
The example above will make mrtg refuse to update log files older than 2 hours (7200 seconds).
With this switch mrtg will generate .meta files
for CERN and Apache servers which contain Expiration tags for the html and gif
files. The *.meta files will be created in the same directory as the other
files, so you will have to set ``MetaDir .'' and ``MetaFiles on'' in your
apache.conf or .htaccess file for this to
work
NOTE: If you are running Apache-1.2 or later,
you can use the mod_expire to achieve the same effect ... see the file
htaccess.txt
Example:
WriteExpires:
Yes
Normally we ask the SNMP device for 'sysUptime'
and 'sysName' properties. Some do not have these. If you want to avoid getting
complaints from mrtg about these missing properties, specify the nomib2
option.
An example of agents which do not implement base
mib2 attributes are Computer Associates - Unicenter TNG Agents. CA relies on
using the base OS SNMP agent in addition to its own agents to supplement the
management of a system.
Example:
# 注释 ：有些设备并不具备 sysUptime 或者 sysName 这些特性。为了防止 MRTG 报错，可以使用 NoMibs2 选项。
NoMib2:
Yes
Some SNMP implementations can not deal with
requests asking for multiple snmp variables in one go. Set this in your cfg file
to force mrtg to only ask for one variable per
request.
Examples ：
# 注释 ：有些 SNMP 的实现不能一次性查询多个 SNMP 对象。所以用 SingleRequest 选项来强迫 MRTG 每个请求只查询一个对象
SingleRequest:
Yes
Apart from the per target timeout options, you can also configure the behaviour of the snmpget process on a more profound level. SnmpOptions accepts a hash of options. The following options are currently supported:
timeout =>
$default_timeout,
retries =>
$default_retries,
backoff =>
$default_backoff,
default_max_repetitions
=>
$max_repetitions,
use_16bit_request_ids
=> 1,
lenient_source_port_matching =>
0,
lenient_source_address_matching =>
1
The values behind the options indicate the
current default value. Note that these settings OVERRIDE the per target timeout
settings.
A per-target SnmpOptions[] keyword will override
the global settings. That keyword is primarily for
SNMPv3.
The 16bit request ids are the only way to query
the broken SNMP implementation of SMC Barricade
routers.
Example:
SnmpOptions: retries
=> 2, only_ip_address_matching =>
0
Note that AS/400 snmp seems to be broken in a way which prevents mrtg from working with it unless
SnmpOptions:
lenient_source_port_matching =>
1
is set.
If you want to keep the mrtg icons in someplace
other than the working (or imagedir) directory, use the IconDir variable
for defining the url of the icons directory.
Example:
# 注释 ：IconDir 选项设置 MRTG 所使用的图标的目录
# 默认是在 WorkDir 或者 Imagedir
IconDir:
/mrtgicons/
Example:
# 注释 ：LoadMIBs 表示加载那些 MIB 。MRTG 会同时把这些
mib 拷贝一份放在 WorkDir 目录下
LoadMIBs:
/dept/net/mibs/netapp.mib,/usr/local/lib/ft100m.mib
Switch output format to the selected Language (Check the translate directory to see which languages are supported at the moment. In this directory you can also find instructions on how to create new translations).
Currently the following laguages are supported:
big5 brazilian bulgarian catalan chinese croatian czech danish dutch eucjp french galician gb gb2312 german greek hungarian icelandic indonesia iso2022jp italian korean lithuanian malay norwegian polish portuguese romanian russian russian1251 serbian slovak slovenian spanish swedish turkish ukrainian
Example:
# 注释 ：Language 设置 HTML 页面的语言。
# 要看当前支持那些语言，可以查看 translate 目录
# 当前支持的语言如上，中文就是 chinese ，gb，gb2312
，繁体中文是 big5
Language:
danish
Setting LogFormat to 'rrdtool' in your mrtg.cfg file
enables rrdtool mode. In rrdtool mode, mrtg relies on rrdtool to do its
logging. See .
Example:
# 注释 ：如果 LogFormat 为 rrdtool ，则 mrtg.cfg 允许 rrdtool 模式的日志，不过要依赖于 rrdtool 来生成日志
LogFormat: rrdtool
If you are using rrdtool mode and your
rrdtool Perl module (RRDs.pm) is not installed in a location where perl
can find it on its own, you can use LibAdd to supply an appropriate
path.
Example:
LibAdd:
/usr/local/rrdtool/lib/perl/
If the
rrdtool executable can not be found in the normal PATH,
you can use this keyword to add a suitable directory to your
path.
Example:
PathAdd:
/usr/local/rrdtool/bin/
The RunAsDaemon keyword enables daemon mode operation. The purpose of daemon mode is that MRTG is launched once and not repeatedly (as it is with cron). This behavior saves computing resourses as loading and parsing of configuration files happens only once.
# 注释 ：RunAsDaemon 关键字允许 MRTG 以守护进程的模式运行。要注意同 cron 运行的方式区别开来。
# 以守护进程模式运行有一个好处就是不用频繁地启动 mrtg 程序，不用重复的读取配置文件，可以节省资源
Using daemon mode MRTG itself is responible for timing the measurement intervals. Therfore its important to set the Interval keyword to an apropiate value.
# 注释 ：由于不是由 crond 控制多长时间调用 mrtg 程序一次，所以 daemon 模式下的 mrtg 就必须设置好 Interval 这个参数
# 由 mrtg 程序自己负责计时工作
Note that when using daemon mode MRTG should no longer be started from cron as each new process runs forever. Instead MRTG should be started from the command prompt or by a system startup script.
# 注释 ：要注意一点，一旦使用了 daemon 模式，mrtg 就不应该以 cron 的方式来启动。
# 应该从命令行启动（并进入 daeon 模式），或者通过 /etc/rc.d/init.d/ 下类似的方式来启动
If you want mrtg to run under a particular user and group (it is not recomended to run MRTG as root) then you can use the --user=user_name and --group=group_name options on the mrtg commandline.
# 注释 ：假如你想要 mrtg 以某个特定的身份来运行（不推荐以
root 身份来运行 mrtg），则需要用到 --user= 和 --group= 两个命令行的选项
mrtg
--user=mrtg_user --group=mrtg_group
mrtg.cfg
Also note that in daemon mode restarting the process is required in order to activate changes in the config file.
# 注释 ：由于处于 daemon 模式，mrtg 并不会自动定时 reload 配置文件，需要手工重启进程
Under UNIX, the Daemon switch causes mrtg to fork into background after checking its config file. On Windows NT the MRTG process will detach from the console, but because the NT/2000 shell waits for its children you have to use this special start sequence when you launch the program:
# 注释 ：在 unix 下，RunAsDaemon 会促使 mrtg 在读取配置文件后自动进入后台，
# 但在 windows NT/2000 下，需要执行 "start /b mrtg mrtg.cf" 命令，才能进入后台，否则会一直处于 cmd 命令窗口下
start /b perl mrtg
mrtg.cfg
You may have to add path information equal to
what you add when you run mrtg from the
commandline.
Example
RunAsDaemon:
Yes
Interval:
5
This makes MRTG run as a daemon beginning data collection every 5 minutes
# 注释 ：上面的配置将使 MRTG 运行在 daemon 模式，每隔5分钟就收集一次数据。
# 所以 MRTG 不会自动去收集数据的，而是通过 Interval 来“强迫” MRTG 去收集数据
# 这和 refresh 是不同的，refresh 是多长时间刷新页面，如果 interval > refresh ，则图表的更新比较及时
# 如果 interval < refresh ，则图表的更新较数据的收集慢，最好是两者差不多
If you are daemontools and still want to run mrtg as a daemon you can additionally specify
NoDetach:
Yes
this will make mrtg run but without detaching it from the terminal.