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Posts Tagged ‘WWW

Apache HTTP Server configuration screen

Image via Wikipedia


  • Apache is a web server, that has it’s roots in the CERN web server.
  •  It is the most widely used web server on the Internet today, it can be integrated with content technologies like Zope, databases like MySQL and PostgreSQL and others (including Oracle and DB2) and the speed and versatility offered by Web rapid application development (RAD) languages like Personal Home Page (PHP).
  •  It is highly configurable, flexible and most importantly,it is open. This had lead to a host of development support on and around Apache.

External modules such as mod_rewrite, mod_perl and mod_php have added fist-fulls of functionality as well as improved the speed with which these requests can be serviced. It has, in no small part, played a role in the acceptance of the Linux platform in corporate organizations.

Apache versions

  • Apache comes in two basic flavors: Apache version 1.3.x and version 2.x.
  •  The configuration of these two differ quite substantially in some places

Basic server design

  • The Apache web server has been designed to be used in either a modular or non-modular way.
  •  In the former, modules are compiled separately from the core Apache server, and loaded dynamically as they are needed. .
  • Generally though, when we unpack an Apache that has been pre-compiled (i.e. It’s already in a .deb or .rpm package format), it is compiled to be modular.

Basic configuration

  • The core Apache server is configured using one text configuration file – httpd.conf. This usually resides in /etc/httpd, but may be elsewhere depending on your distribution.
  • The httpd.conf file is fairly well documented, however there are additional documentation with Apache that is an excellent resource to keep handy.

The server has 3 sections to the configuration file:

1. The global configuration settings

2. The main server configuration settings

3. The virtual hosts

Global configuration settings

In this part of the configuration file, the settings affect the overall operation of the server. Setting such as the minimum number of servers to start, the maximum number of servers to start, the server root directory and what port to listen on for http requests (the default port is 80, although you may make this whatever you wish).

Main server configuration settings

The majority of the server configuration happens within this section of the file. This is where we specify the DocumentRoot, the place we put our web pages that we want served to the public. This is where permissions for accessing the directories are defined and where authentication is configured.

The virtual hosts section

  • Hosting of many sites does not require many servers. Apache has the ability to divide it’s time by offering web pages for different web sites. The web site www.QEDux.co.za, is hosted on the same web server as http://www.hamishwhittal.org.za.
  • Apache is operating as a virtual host – it’s offering two sites from a single server.

IIS has three level of isolation:-

  1. LOW (IIS process)
  2. Medium pooled scenario
  3. High isolation scenario

LOW (IIS process):

  • In this main IIS process and ASP.NET application run in same process.
  •  So if any one crashes the other is also affected.

Example : It is possible to  host yahoo, hotmail .amazon and google on a single PC. So all application and the IIS process runs on the same process. In case any website crashes it affects every one.

Medium (Pooled):

  • In Medium pooled scenario the IIS and web application run in different process.
  • So in this case there are two processes process1 and process2.
  • In process1 the IIS process is running and in process2 we have all Web application running.

High (Isolated):

  • In high isolated scenario every process is running is there own process.
  • In given figure of high isolated scenario,there are five processes and every one   individual application.this requires heavy memory capacity with high fidelity.

                                       High isolation scenario

Medium pooled scenario

LOW IIS process scenario


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