Manage Apache download speed & Traffic Speeds

In this tutorial I will show you how to install & setup mod_cband on RHEL/CentOS/Fedora (64-bit version)

Note: mod_cband is an Apache2 module, it does not work with Apache 1.3.x!

 

1. Installation

In order to compile mod_cband, we must have apxs installed. We can achieve that by doing this:

yum install httpd-devel

Next we download and install mod_cband like this:

cd /tmp

wget http://cband.linux.pl/download/mod-cband-0.9.7.4.tgz

tar xzvf mod-cband-0.9.7.4.tgz

cd mod-cband-0.9.7.4

./configure && make && make install

The make install command should have added the mod_cband module to /etc/httpd/conf/httpd.conf. Run

vi /etc/httpd/conf/httpd.conf

and check if you find a line like this:

LoadModule cband_module       /usr/lib64/httpd/modules/mod_cband.so

(If you don’t find this line, add it yourself.)

Finallly restart Apache:

/etc/init.d/httpd restart

The mod_cband installation is now finished.

You can find all configuration directives on mod_cband’s documentation pagehttp://cband.linux.pl/documentation. I will describe the most important ones here on virtual host:

<VirtualHost 1.2.3.4>
ServerName www.mylinuxtips.info
ServerAdmin [email protected]
DocumentRoot /var/www
</VirtualHost>

Please note: It is important that your vhost includes the ServerName directive (e.g. ServerName www.mylinuxtips.info) and that your mod_cband directives come after that directive, otherwise you will get a warning like this when you restart Apache:

[warn] Invalid command ‘CBandSpeed’, undefined virtualhost name

You can use the following units in the mod_cband directives:

Transfer speeds:

  • kbps: 1024 bits per second
  • Mbps: 1024*1024 bits per second
  • Gbps: 1024*1024*1024 bits per second
  • The default is kbps.

Transfer quotas:

  • K: 1000 bytes
  • M: 1000*1000 bytes
  • G: 1000*1000*1000 bytes
  • Ki: 1024 bytes
  • Mi: 1024*1024 bytes
  • Gi: 1024*1024*1024 bytes
  • The default is K.

Time periods:

  • S: seconds
  • M: minutes
  • H: hours
  • D: days
  • W: weeks
  • The default is S.

First we add the following two directives to the global Apache configuration (not to the vhost from above!). They are needed to improve mod_cband’s performance.

vi /etc/httpd/conf/httpd.conf

CBandScoreFlushPeriod 1
CBandRandomPulse On

Now we create the scoreboard directory for our www.mylinuxtips.info vhost, /var/www/scoreboard. The directory must be writeable by the Apache user:

1.1 Configure Download Speed

Now let’s say we want to limit the download speed. We can do it like this:

<VirtualHost 1.2.3.4>

ServerName www.mylinuxtips.info

ServerAdmin [email protected]

DocumentRoot /var/www

CBandSpeed 1024 10 30

CBandRemoteSpeed 20kb/s 3 3

</VirtualHost>

The CBandSpeed directive limits the overall Apache performance for the www.mylinuxtips.info vhost to a speed of 1024kbps, max. 10 requests per second and max. 30 open connections.

The CBandRemoteSpeed is like the CBandSpeed directive, but it sets limits for any individual user (as compared to the overall settings made by CBandSpeed).

After your changes, you must restart Apache:

/etc/init.d/httpd restart

In the next example we want to give our vhost www.mylinuxtips.info a traffic limit of 100MB per month, and if that limit is exceeded, we want to limit the download speed to 128kbps, max. 5 requests per second and max. 15 open connections:

<VirtualHost 1.2.3.4>

ServerName www.mylinuxtips.info
ServerAdmin [email protected]
DocumentRoot /var/www
CBandLimit 100M
CBandExceededSpeed 128 5 15
CBandScoreboard /var/www/scoreboard
CBandPeriod 4W

</VirtualHost>

The directives are pretty self-explanatory. The CBandPeriod directive specifies after what time the traffic counter is reset to 0.
The next example is pretty similar, but now we don’t want the speed to be limited if the traffic is exceeded, no, we get more restrictive and deliver a 503 status page instead:

<VirtualHost 1.2.3.4>
ServerName www.mylinuxtips.info
ServerAdmin [email protected]
DocumentRoot /var/www
CBandLimit 100M
CBandScoreboard /var/www/scoreboard
CBandPeriod 4W
</VirtualHost>

If you want to redirect the user to a URL instead of presenting a 503 error to him, you can do it like this:

<VirtualHost 1.2.3.4>
ServerName www.mylinuxtips.info
ServerAdmin [email protected]
DocumentRoot /var/www
CBandLimit 100M
CBandExceededURL https://mylinuxtips.info/traffic_exceeded.html
CBandScoreboard /var/www/scoreboard
CBandPeriod 4W
</VirtualHost>

Please note: the CBandExceededSpeed and the CBandExceededURL directives are mutually exclusive. They do not make sense in the same vhost! After your changes, you must restart Apache:

/etc/init.d/httpd restart

2. Status Page

To view the current bandwidth limits, usages, users, scoreboards, add the following Location lines to the vhost configuration:

<VirtualHost 1.2.3.4>

ServerName www.mylinuxtips.info

ServerAdmin [email protected]mylinuxtips.info

DocumentRoot /var/www

CBandLimit 100M

CBandExceededSpeed 128 5 15

CBandScoreboard /var/www/scoreboard

CBandPeriod 4W

<Location /cband-status>

  SetHandler cband-status

</Location>

<Location /cband-status-me>

  SetHandler cband-status-me

</Location>

</VirtualHost>

Restart Apache, and afterwards you can find the status pages under https://mylinuxtips.info/cband-status and https://mylinuxtips.info/cband-status-me

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