The Apache HTTP Server, commonly referred to as Apache , is web server software notable for playing a key place in the initial broadening of the Set Extensive Web. In 2009 it became the ahead web server software to pass beyond the 100 million website milestone. Apache was the first rapport selection to the Netscape Communications Corporation trap server (currently known as Oracle iPlanet Network Server), and has since evolved to contest other web servers in terms of functionality and performance. Typically Apache is manufacture on a Unix-like operating system.
Apache is developed and maintained by an public community of developers underneath the approval of the Apache Software Foundation. The utilization is available for a deviating selection of operating systems, including Unix, GNU, FreeBSD, Linux, Solaris, Novell NetWare, AmigaOS, Mac OS X, Microsoft Windows, OS/2, TPF, and eComStation. Released impaired the Apache License, Apache is open-source software.
Since April 1996 Apache has been the most conventional HTTP server software in use. As of May 2011 Apache was estimated to serve 63% of all websites and 66% of the million busiest.
Features

Apache supports a breed of features, tons implemented as compiled modules which proffer the pit functionality. These can latitude from server-side programming phrasing assist to authentication schemes. Some conventional lingua franca interfaces buttress Perl, Python, Tcl, and PHP. Favoured authentication modules take in mod_access, mod_auth, mod_pr‚cis, and mod_auth_synopsis, the successor to mod_digest. A example of other features embrace SSL and TLS supporter (mod_ssl), a proxy module (mod_agent), a URL rewriter (also known as a rewrite apparatus, implemented lower than drunk mod_rewrite), routine log files (mod_log_config), and filtering sustain (mod_contain and mod_ext_eliminate).
In demand compression methods on Apache categorize the exotic height module, mod_gzip, implemented to help with reduction of the scope (strain) of web pages served over HTTP. ModSecurity is an uncover begetter intrusion detection and interception machine object of web applications. Apache logs can be analyzed in the course a entanglement browser using delivered scripts such as AWStats/W3Perl or Visitors.
Virtual hosting allows one Apache station to help uncountable unalike actual websites. For benchmark, the same machine with united Apache consecration could simultaneously be in the service of www.example.com, www.test.com, test47.test-server.test.com, etc.
Apache features configurable slip-up messages, DBMS-based authentication databases, and content negotiation. It is also supported by respective graphical drug interfaces (GUIs).
It supports open sesame authentication and digital certificate authentication. Apache has a built in search engine and an HTML authorizing contraption and supports FTP.

Performance


This fraction does not cite any references or sources. Content cure enhance this section near adding citations to principled sources. Unsourced fabric may be challenged and removed. (October 2009)
Although the main cabal object of Apache is not to be the "fastest" entanglement server, Apache does have fulfilment comparable to other "high-performance" web servers. In lieu of of implementing a fix architecture, Apache provides a choice of MultiProcessing Modules (MPMs) which permit Apache to skip out in a process-based, half-breed (process and motif) or event-hybrid look, to excel meet the demands of each separate infrastructure. This implies that the choice of chasten MPM and the correct configuration is important. Where compromises in performance lack to be made, the lay out of Apache is to humble latency and gain throughput, relative to austerely handling more requests, in which case ensuring in concordance and honourable processing of requests within tenable time-frames.
The Apache version considered past the Apache Fundamental as providing high-performance is the multi-threaded adaptation which mixes the use of a handful processes and several threads per process.
While this architecture works faster than the erstwhile multi-process based topology (because threads suffer with a trim outlay than processes), it does not accord the performances of the event-based architecture provided away other servers, unusually when they prepare events with a variety of workman threads.
This inequality can be easily explained beside the high up that one thread per relevance brings (as opposed to a couple of worker threads per CPU, each processing profuse connection events). Each thread needs to uphold its own stack, milieu, and switching from joke thread to another is also an high-priced censure in search CPUs.