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   8 <title>Multi-Processing Modules (MPMs) - Apache HTTP Server</title>
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  15 <p class="apache">Apache HTTP Server Version 2.3</p>
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  19 <a href="http://www.apache.org/">Apache</a> &gt; <a href="http://httpd.apache.org/">HTTP Server</a> &gt; <a href="http://httpd.apache.org/docs/">Documentation</a> &gt; <a href="./">Version 2.3</a></div><div id="page-content"><div id="preamble"><h1>Multi-Processing Modules (MPMs)</h1>
  20 <div class="toplang">
  21 <p><span>Available Languages: </span><a href="./de/mpm.html" hreflang="de" rel="alternate" title="Deutsch">&nbsp;de&nbsp;</a> |
  22 <a href="./en/mpm.html" title="English">&nbsp;en&nbsp;</a> |
  23 <a href="./es/mpm.html" hreflang="es" rel="alternate" title="Español">&nbsp;es&nbsp;</a> |
  24 <a href="./fr/mpm.html" hreflang="fr" rel="alternate" title="Français">&nbsp;fr&nbsp;</a> |
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  26 <a href="./ko/mpm.html" hreflang="ko" rel="alternate" title="Korean">&nbsp;ko&nbsp;</a> |
  27 <a href="./tr/mpm.html" hreflang="tr" rel="alternate" title="Türkçe">&nbsp;tr&nbsp;</a></p>
  28 </div>
  29
  30 <p>This document describes what a Multi-Processing Module is and
  31 how they are used by the Apache HTTP Server.</p>
  32 </div>
  33 <div id="quickview"><ul id="toc"><li><img alt="" src="./images/down.gif" /> <a href="#introduction">Introduction</a></li>
  34 <li><img alt="" src="./images/down.gif" /> <a href="#choosing">Choosing an MPM</a></li>
  35 <li><img alt="" src="./images/down.gif" /> <a href="#defaults">MPM Defaults</a></li>
  36 </ul></div>
  37 <div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
  38 <div class="section">
  39 <h2><a name="introduction" id="introduction">Introduction</a></h2>
  40
  41     <p>The Apache HTTP Server is designed to be a powerful and
  42     flexible web server that can work on a very wide variety of
  43     platforms in a range of different environments. Different
  44     platforms and different environments often require different
  45     features, or may have different ways of implementing the same
  46     feature most efficiently. Apache has always accommodated a wide
  47     variety of environments through its modular design. This design
  48     allows the webmaster to choose which features will be included
  49     in the server by selecting which modules to load either at
  50     compile-time or at run-time.</p>
  51
  52     <p>Apache 2.0 extends this modular design to the most basic
  53     functions of a web server. The server ships with a selection of
  54     Multi-Processing Modules (MPMs) which are responsible for
  55     binding to network ports on the machine, accepting requests,
  56     and dispatching children to handle the requests.</p>
  57
  58     <p>Extending the modular design to this level of the server
  59     allows two important benefits:</p>
  60
  61     <ul>
  62       <li>Apache can more cleanly and efficiently support a wide
  63       variety of operating systems. In particular, the Windows
  64       version of Apache is now much more efficient, since
  65       <code class="module"><a href="./mod/mpm_winnt.html">mpm_winnt</a></code> can use native
  66       networking features in place of the POSIX layer used in
  67       Apache 1.3. This benefit also extends to other operating
  68       systems that implement specialized MPMs.</li>
  69
  70       <li>The server can be better customized for the needs of the
  71       particular site. For example, sites that need a great deal of
  72       scalability can choose to use a threaded MPM like
  73       <code class="module"><a href="./mod/worker.html">worker</a></code> or <code class="module"><a href="./mod/event.html">event</a></code>, while sites requiring
  74       stability or compatibility with older software can use a
  75       <code class="module"><a href="./mod/prefork.html">prefork</a></code>.</li>
  76     </ul>
  77
  78     <p>At the user level, MPMs appear much like other Apache
  79     modules. The main difference is that one and only one MPM must
  80     be loaded into the server at any time. The list of available
  81     MPMs appears on the <a href="mod/">module index page</a>.</p>
  82
  83 </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
  84 <div class="section">
  85 <h2><a name="choosing" id="choosing">Choosing an MPM</a></h2>
  86
  87     <p>MPMs must be chosen during configuration, and compiled into
  88     the server. Compilers are capable of optimizing a lot of
  89     functions if threads are used, but only if they know that
  90     threads are being used.</p>
  91
  92     <p>To actually choose the desired MPM, use the argument
  93       <code>--with-mpm=<em>NAME</em></code> with the
  94       <code class="program"><a href="./programs/configure.html">configure</a></code> script. <em>NAME</em> is the name of the
  95       desired MPM.</p>
  96
  97     <p>Once the server has been compiled, it is possible to
  98     determine which MPM was chosen by using <code>./httpd
  99     -l</code>. This command will list every module that is compiled
 100     into the server, including the MPM.</p>
 101 </div><div class="top"><a href="#page-header"><img alt="top" src="./images/up.gif" /></a></div>
 102 <div class="section">
 103 <h2><a name="defaults" id="defaults">MPM Defaults</a></h2>
 104
 105 <p>The following table lists the default MPMs for various operating
 106 systems.  This will be the MPM selected if you do not make another
 107 choice at compile-time.</p>
 108
 109 <table>
 110
 111 <tr><td>BeOS</td><td><code class="module"><a href="./mod/beos.html">beos</a></code></td></tr>
 112 <tr><td>Netware</td><td><code class="module"><a href="./mod/mpm_netware.html">mpm_netware</a></code></td></tr>
 113 <tr><td>OS/2</td><td><code class="module"><a href="./mod/mpmt_os2.html">mpmt_os2</a></code></td></tr>
 114 <tr><td>Unix</td><td><code class="module"><a href="./mod/prefork.html">prefork</a></code></td></tr>
 115 <tr><td>Windows</td><td><code class="module"><a href="./mod/mpm_winnt.html">mpm_winnt</a></code></td></tr>
 116 </table>
 117 </div></div>
 118 <div class="bottomlang">
 119 <p><span>Available Languages: </span><a href="./de/mpm.html" hreflang="de" rel="alternate" title="Deutsch">&nbsp;de&nbsp;</a> |
 120 <a href="./en/mpm.html" title="English">&nbsp;en&nbsp;</a> |
 121 <a href="./es/mpm.html" hreflang="es" rel="alternate" title="Español">&nbsp;es&nbsp;</a> |
 122 <a href="./fr/mpm.html" hreflang="fr" rel="alternate" title="Français">&nbsp;fr&nbsp;</a> |
 123 <a href="./ja/mpm.html" hreflang="ja" rel="alternate" title="Japanese">&nbsp;ja&nbsp;</a> |
 124 <a href="./ko/mpm.html" hreflang="ko" rel="alternate" title="Korean">&nbsp;ko&nbsp;</a> |
 125 <a href="./tr/mpm.html" hreflang="tr" rel="alternate" title="Türkçe">&nbsp;tr&nbsp;</a></p>
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 127 <p class="apache">Copyright 2009 The Apache Software Foundation.<br />Licensed under the <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache License, Version 2.0</a>.</p>
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