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| author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-07 02:04:06 +0000 |
|---|---|---|
| committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-07 02:04:06 +0000 |
| commit | 5dff2d61cc1c27747ee398e04d8e02843aabb1f8 (patch) | |
| tree | a67c336b406c8227bac912beb74a1ad3cdc55100 /docs/manual/mod/prefork.html.en | |
| parent | Initial commit. (diff) | |
| download | apache2-5dff2d61cc1c27747ee398e04d8e02843aabb1f8.tar.xz apache2-5dff2d61cc1c27747ee398e04d8e02843aabb1f8.zip | |
Adding upstream version 2.4.38.upstream/2.4.38
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'docs/manual/mod/prefork.html.en')
| -rw-r--r-- | docs/manual/mod/prefork.html.en | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/docs/manual/mod/prefork.html.en b/docs/manual/mod/prefork.html.en new file mode 100644 index 0000000..0780b75 --- /dev/null +++ b/docs/manual/mod/prefork.html.en @@ -0,0 +1,218 @@ +<?xml version="1.0" encoding="ISO-8859-1"?> +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head> +<meta content="text/html; charset=ISO-8859-1" http-equiv="Content-Type" /> +<!-- + XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX + This file is generated from xml source: DO NOT EDIT + XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX + --> +<title>prefork - Apache HTTP Server Version 2.4</title> +<link href="../style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" /> +<link href="../style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" /> +<link href="../style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" /><link rel="stylesheet" type="text/css" href="../style/css/prettify.css" /> +<script src="../style/scripts/prettify.min.js" type="text/javascript"> +</script> + +<link href="../images/favicon.ico" rel="shortcut icon" /></head> +<body> +<div id="page-header"> +<p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p> +<p class="apache">Apache HTTP Server Version 2.4</p> +<img alt="" src="../images/feather.png" /></div> +<div class="up"><a href="./"><img title="<-" alt="<-" src="../images/left.gif" /></a></div> +<div id="path"> +<a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs/">Documentation</a> > <a href="../">Version 2.4</a> > <a href="./">Modules</a></div> +<div id="page-content"> +<div id="preamble"><h1>Apache MPM prefork</h1> +<div class="toplang"> +<p><span>Available Languages: </span><a href="../de/mod/prefork.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> | +<a href="../en/mod/prefork.html" title="English"> en </a> | +<a href="../fr/mod/prefork.html" hreflang="fr" rel="alternate" title="Français"> fr </a> | +<a href="../ja/mod/prefork.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> | +<a href="../tr/mod/prefork.html" hreflang="tr" rel="alternate" title="Türkçe"> tr </a></p> +</div> +<table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Implements a non-threaded, pre-forking web server</td></tr> +<tr><th><a href="module-dict.html#Status">Status:</a></th><td>MPM</td></tr> +<tr><th><a href="module-dict.html#ModuleIdentifier">Module Identifier:</a></th><td>mpm_prefork_module</td></tr> +<tr><th><a href="module-dict.html#SourceFile">Source File:</a></th><td>prefork.c</td></tr></table> +<h3>Summary</h3> + + <p>This Multi-Processing Module (MPM) implements a non-threaded, + pre-forking web server. Each server process may answer incoming + requests, and a parent process manages the size of the server pool. + It is appropriate for sites that need to avoid + threading for compatibility with non-thread-safe libraries. It + is also the best MPM for isolating each request, so that a problem + with a single request will not affect any other.</p> + + <p>This MPM is very self-regulating, so it is rarely necessary to + adjust its configuration directives. Most important is that + <code class="directive"><a href="../mod/mpm_common.html#maxrequestworkers">MaxRequestWorkers</a></code> be big enough + to handle as many simultaneous requests as you expect to receive, but + small enough to assure that there is enough physical RAM for all + processes.</p> +</div> +<div id="quickview"><a href="https://www.apache.org/foundation/contributing.html" class="badge"><img src="https://www.apache.org/images/SupportApache-small.png" alt="Support Apache!" /></a><h3>Topics</h3> +<ul id="topics"> +<li><img alt="" src="../images/down.gif" /> <a href="#how-it-works">How it Works</a></li> +</ul><h3 class="directives">Directives</h3> +<ul id="toc"> +<li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#coredumpdirectory">CoreDumpDirectory</a></li> +<li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#enableexceptionhook">EnableExceptionHook</a></li> +<li><img alt="" src="../images/right.gif" /> <a href="mod_unixd.html#group">Group</a></li> +<li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#listen">Listen</a></li> +<li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#listenbacklog">ListenBacklog</a></li> +<li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#maxconnectionsperchild">MaxConnectionsPerChild</a></li> +<li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#maxmemfree">MaxMemFree</a></li> +<li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#maxrequestworkers">MaxRequestWorkers</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#maxspareservers">MaxSpareServers</a></li> +<li><img alt="" src="../images/down.gif" /> <a href="#minspareservers">MinSpareServers</a></li> +<li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#pidfile">PidFile</a></li> +<li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#receivebuffersize">ReceiveBufferSize</a></li> +<li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#scoreboardfile">ScoreBoardFile</a></li> +<li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#sendbuffersize">SendBufferSize</a></li> +<li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#serverlimit">ServerLimit</a></li> +<li><img alt="" src="../images/right.gif" /> <a href="mpm_common.html#startservers">StartServers</a></li> +<li><img alt="" src="../images/right.gif" /> <a href="mod_unixd.html#user">User</a></li> +</ul> +<h3>Bugfix checklist</h3><ul class="seealso"><li><a href="https://www.apache.org/dist/httpd/CHANGES_2.4">httpd changelog</a></li><li><a href="https://bz.apache.org/bugzilla/buglist.cgi?bug_status=__open__&list_id=144532&product=Apache%20httpd-2&query_format=specific&order=changeddate%20DESC%2Cpriority%2Cbug_severity&component=mpm_prefork">Known issues</a></li><li><a href="https://bz.apache.org/bugzilla/enter_bug.cgi?product=Apache%20httpd-2&component=mpm_prefork">Report a bug</a></li></ul><h3>See also</h3> +<ul class="seealso"> +<li><a href="../bind.html">Setting which addresses and ports Apache HTTP Server +uses</a></li> +<li><a href="#comments_section">Comments</a></li></ul></div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="section"> +<h2><a name="how-it-works" id="how-it-works">How it Works</a></h2> + <p>A single control process is responsible for launching child + processes which listen for connections and serve them when they + arrive. Apache httpd always tries to maintain several <dfn>spare</dfn> + or idle server processes, which stand ready to serve incoming + requests. In this way, clients do not need to wait for a new + child processes to be forked before their requests can be + served.</p> + + <p>The <code class="directive"><a href="../mod/mpm_common.html#startservers">StartServers</a></code>, + <code class="directive"><a href="#minspareservers">MinSpareServers</a></code>, + <code class="directive"><a href="#maxspareservers">MaxSpareServers</a></code>, and + <code class="directive"><a href="../mod/mpm_common.html#maxrequestworkers">MaxRequestWorkers</a></code> regulate how + the parent process creates children to serve requests. In general, + Apache httpd is very self-regulating, so most sites do not need to + adjust these directives from their default values. Sites which + need to serve more than 256 simultaneous requests may need to + increase <code class="directive"><a href="../mod/mpm_common.html#maxrequestworkers">MaxRequestWorkers</a></code>, + while sites with limited memory may need to decrease <code class="directive"><a href="../mod/mpm_common.html#maxrequestworkers">MaxRequestWorkers</a></code> to keep the server from + thrashing (swapping memory to disk and back). More information + about tuning process creation is provided in the <a href="../misc/perf-tuning.html">performance hints</a> + documentation.</p> + + <p>While the parent process is usually started as <code>root</code> + under Unix in order to bind to port 80, the child processes are + launched by Apache httpd as a less-privileged user. The <code class="directive"><a href="../mod/mod_unixd.html#user">User</a></code> and <code class="directive"><a href="../mod/mod_unixd.html#group">Group</a></code> directives are used to set + the privileges of the Apache httpd child processes. The child processes + must be able to read all the content that will be served, but + should have as few privileges beyond that as possible.</p> + + <p><code class="directive"><a href="../mod/mpm_common.html#maxconnectionsperchild">MaxConnectionsPerChild</a></code> + controls how frequently the server recycles processes by killing + old ones and launching new ones.</p> + + <p>This MPM uses the <code>mpm-accept</code> mutex to serialize + access to incoming connections when subject to the thundering herd + problem (generally, when there are multiple listening sockets). + The implementation aspects of this mutex can be configured with the + <code class="directive"><a href="../mod/core.html#mutex">Mutex</a></code> directive. The <a href="../misc/perf-tuning.html">performance hints</a> + documentation has additional information about this mutex.</p> +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="MaxSpareServers" id="MaxSpareServers">MaxSpareServers</a> <a name="maxspareservers" id="maxspareservers">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maximum number of idle child server processes</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxSpareServers <var>number</var></code></td></tr> +<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxSpareServers 10</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>MPM</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>prefork</td></tr> +</table> + <p>The <code class="directive">MaxSpareServers</code> directive sets the + desired maximum number of <em>idle</em> child server processes. An + idle process is one which is not handling a request. If there are + more than <code class="directive">MaxSpareServers</code> idle, then the + parent process will kill off the excess processes.</p> + + <p>Tuning of this parameter should only be necessary on very + busy sites. Setting this parameter to a large number is almost + always a bad idea. If you are trying to set the value equal to or lower than + <code class="directive"><a href="#minspareservers">MinSpareServers</a></code>, Apache HTTP Server + will automatically adjust it to <code class="directive">MinSpareServers</code><code> + 1</code>.</p> + +<h3>See also</h3> +<ul> +<li><code class="directive"><a href="#minspareservers">MinSpareServers</a></code></li> +<li><code class="directive"><a href="../mod/mpm_common.html#startservers">StartServers</a></code></li> +<li><code class="directive"><a href="../mod/mpm_common.html#maxsparethreads">MaxSpareThreads</a></code></li> +</ul> +</div> +<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> +<div class="directive-section"><h2><a name="MinSpareServers" id="MinSpareServers">MinSpareServers</a> <a name="minspareservers" id="minspareservers">Directive</a></h2> +<table class="directive"> +<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Minimum number of idle child server processes</td></tr> +<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MinSpareServers <var>number</var></code></td></tr> +<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MinSpareServers 5</code></td></tr> +<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr> +<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>MPM</td></tr> +<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>prefork</td></tr> +</table> + <p>The <code class="directive">MinSpareServers</code> directive sets the + desired minimum number of <em>idle</em> child server processes. An + idle process is one which is not handling a request. If there are + fewer than <code class="directive">MinSpareServers</code> idle, then the parent + process creates new children: It will spawn one, wait a second, then spawn + two, wait a second, then spawn four, and it will + continue exponentially until it is spawning 32 children per second. It will + stop whenever it satisfies the <code class="directive">MinSpareServers</code> + setting.</p> + + <p>Tuning of this parameter should only be necessary on very + busy sites. Setting this parameter to a large number is almost + always a bad idea.</p> + +<h3>See also</h3> +<ul> +<li><code class="directive"><a href="#maxspareservers">MaxSpareServers</a></code></li> +<li><code class="directive"><a href="../mod/mpm_common.html#startservers">StartServers</a></code></li> +<li><code class="directive"><a href="../mod/mpm_common.html#minsparethreads">MinSpareThreads</a></code></li> +</ul> +</div> +</div> +<div class="bottomlang"> +<p><span>Available Languages: </span><a href="../de/mod/prefork.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> | +<a href="../en/mod/prefork.html" title="English"> en </a> | +<a href="../fr/mod/prefork.html" hreflang="fr" rel="alternate" title="Français"> fr </a> | +<a href="../ja/mod/prefork.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> | +<a href="../tr/mod/prefork.html" hreflang="tr" rel="alternate" title="Türkçe"> tr </a></p> +</div><div class="top"><a href="#page-header"><img src="../images/up.gif" alt="top" /></a></div><div class="section"><h2><a id="comments_section" name="comments_section">Comments</a></h2><div class="warning"><strong>Notice:</strong><br />This is not a Q&A section. Comments placed here should be pointed towards suggestions on improving the documentation or server, and may be removed again by our moderators if they are either implemented or considered invalid/off-topic. Questions on how to manage the Apache HTTP Server should be directed at either our IRC channel, #httpd, on Freenode, or sent to our <a href="http://httpd.apache.org/lists.html">mailing lists</a>.</div> +<script type="text/javascript"><!--//--><![CDATA[//><!-- +var comments_shortname = 'httpd'; +var comments_identifier = 'http://httpd.apache.org/docs/2.4/mod/prefork.html'; +(function(w, d) { + if (w.location.hostname.toLowerCase() == "httpd.apache.org") { + d.write('<div id="comments_thread"><\/div>'); + var s = d.createElement('script'); + s.type = 'text/javascript'; + s.async = true; + s.src = 'https://comments.apache.org/show_comments.lua?site=' + comments_shortname + '&page=' + comments_identifier; + (d.getElementsByTagName('head')[0] || d.getElementsByTagName('body')[0]).appendChild(s); + } + else { + d.write('<div id="comments_thread">Comments are disabled for this page at the moment.<\/div>'); + } +})(window, document); +//--><!]]></script></div><div id="footer"> +<p class="apache">Copyright 2019 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> +<p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p></div><script type="text/javascript"><!--//--><![CDATA[//><!-- +if (typeof(prettyPrint) !== 'undefined') { + prettyPrint(); +} +//--><!]]></script> +</body></html>
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