Mod_Security

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EasyApache

RLimits

RLimits

Resource limits, or RLimits, are sometimes appropriate on older hardware, or if a customer requests them specifically. It can only be set on  VPS/Dedicated servers. 

RLimits can be added to :-

 

# /usr/local/apache/conf/include/pre_main_global.conf

The most common entries are: Limits memory usage to 100MB. (note: will not work on VZ VPS)

RLimitMEM 104857600 104857600

Limits CPU usage.

RLimitCPU 150 200

Limits Number of processes per user (This is what regulates the process limits on shared servers).

RLimitNPROC 25 30

Mod_Expires/_Cache/_PageSpeed/_Bandwidth/_

Mod_Expires

The mod_expires module allows Cache-Control and expires headers to be added to a site without any changes to the existing site code. You can determine if a site is already providing cache headers by checking the current site headers: No caching headers:

~ $ curl -I http://www.hostgator.com
HTTP/1.1 200 OK
Date: Wed, 22 Sep 2010 20:30:25 GMT
Server: Apache/2.2.3 (CentOS)
Accept-Ranges: bytes
Content-Type: text/html; charset=UTF-8

Cloudflare's caching headers:

HTML:
HTTP/1.1 200 OK
Server: cloudflare-nginx
Date: Wed, 22 Sep 2010 20:19:51 GMT
Content-Type: text/html; charset=UTF-8
Connection: keep-alive
ETag: "a568013-14dd2-490de3c42e8c0"
Accept-Ranges: bytes
Cache-Control: max-age=300, must-revalidate
Expires: Wed, 22 Sep 2010 20:24:48 GMT

Image:
HTTP/1.1 200 OK
Server: cloudflare-nginx
Date: Wed, 22 Sep 2010 20:19:56 GMT
Content-Type: image/jpeg
Connection: keep-alive
Last-Modified: Tue, 03 Aug 2010 03:10:53 GMT
ETag: "a5683b0-10558-48ce2aa35e940"
Accept-Ranges: bytes
Content-Length: 66904
Expires: Wed, 22 Sep 2010 22:19:56 GMT
Cache-Control: max-age=7200

Note how the image is being cached for 2 hours while the html is only being cached for 5 minutes. You can reproduce those settings with the following .htaccess rules.

<filesmatch "\.(flv|gif|ico|jpg|jpeg|png|swf)$">
    header set Cache-Control "max-age=2592000"
</filesmatch>
<filesmatch "\.(css|js|pdf|txt)$">
    header set Cache-Control "max-age=604800"
</filesmatch>
<filesmatch "\.(html|htm)$">
    header set Cache-Control "max-age=43200"
</filesmatch>
<filesmatch "\.(cgi|fcgi|php|pl|scgi|spl)$">
    header unset Cache-Control
    <ifmodule mod_expires.c>
        expiresactive off
    </ifmodule>
</filesmatch>
<ifmodule mod_expires.c>
    expiresdefault "access plus 1 year"
</ifmodule>





Mod_Cache and Mod_Pagespeed

mod_pagespeed

mod_pagespeed is an Apache module that adjusts html output to help the page render faster in the clients browser and performs some caching for the output as well. Some of the more common tasks would be removing whitespaces between html code, unifying CSS and java scripts into one file, gziping and rearranging the html on the page. 

Install script:

GET http://hgfix.net/heckel/install-pagespeed | bash

Mod_Bandwidth :-

"Mod_bandwidth" is a module for the Apache HTTP webserver that enable the setting of server-wide or per connection bandwidth limits, based on the directory, size of files and remote IP/domain. 

You can find the specific file types affected and other configuration settings in the "/usr/local/apache/conf/includes/mod_bandwidth.conf" file.