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Obtained from: Sander Striker git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@96782 13f79535-47bb-0310-9956-ffa450edef68
508 lines
47 KiB
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508 lines
47 KiB
XML
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
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--><title>mpm_common - Apache HTTP Server</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 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="../faq/">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p><p class="apache">Apache HTTP Server Version 2.0</p><img alt="" src="../images/feather.gif" /></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-project/">Documentation</a> > <a href="../">Version 2.0</a> > <a href="./">Modules</a></div><div id="page-content"><div id="preamble"><h1>Apache Module mpm_common</h1><table class="module"><tr><th><a href="module-dict.html#Description">Description:
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</a></th><td>A collection of directives that are implemented by
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more than one multi-processing module (MPM)</td></tr><tr><th><a href="module-dict.html#Status">Status:
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</a></th><td>MPM</td></tr></table></div><div id="quickview"><h3 class="directives">Directives</h3><ul id="toc"><li><img alt="" src="../images/down.gif" /> <a href="#coredumpdirectory">CoreDumpDirectory</a></li><li><img alt="" src="../images/down.gif" /> <a href="#group">Group</a></li><li><img alt="" src="../images/down.gif" /> <a href="#listen">Listen</a></li><li><img alt="" src="../images/down.gif" /> <a href="#listenbacklog">ListenBackLog</a></li><li><img alt="" src="../images/down.gif" /> <a href="#lockfile">LockFile</a></li><li><img alt="" src="../images/down.gif" /> <a href="#maxclients">MaxClients</a></li><li><img alt="" src="../images/down.gif" /> <a href="#maxmemfree">MaxMemFree</a></li><li><img alt="" src="../images/down.gif" /> <a href="#maxrequestsperchild">MaxRequestsPerChild</a></li><li><img alt="" src="../images/down.gif" /> <a href="#maxsparethreads">MaxSpareThreads</a></li><li><img alt="" src="../images/down.gif" /> <a href="#maxthreadsperchild">MaxThreadsPerChild</a></li><li><img alt="" src="../images/down.gif" /> <a href="#minsparethreads">MinSpareThreads</a></li><li><img alt="" src="../images/down.gif" /> <a href="#numservers">NumServers</a></li><li><img alt="" src="../images/down.gif" /> <a href="#pidfile">PidFile</a></li><li><img alt="" src="../images/down.gif" /> <a href="#scoreboardfile">ScoreBoardFile</a></li><li><img alt="" src="../images/down.gif" /> <a href="#sendbuffersize">SendBufferSize</a></li><li><img alt="" src="../images/down.gif" /> <a href="#serverlimit">ServerLimit</a></li><li><img alt="" src="../images/down.gif" /> <a href="#startservers">StartServers</a></li><li><img alt="" src="../images/down.gif" /> <a href="#startthreads">StartThreads</a></li><li><img alt="" src="../images/down.gif" /> <a href="#threadlimit">ThreadLimit</a></li><li><img alt="" src="../images/down.gif" /> <a href="#threadsperchild">ThreadsPerChild</a></li><li><img alt="" src="../images/down.gif" /> <a href="#user">User</a></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="CoreDumpDirectory" id="CoreDumpDirectory">CoreDumpDirectory</a> <a name="coredumpdirectory" id="coredumpdirectory">Directive</a></h2><table class="directive"><tr><th><a href="directive-dict.html#Description">Description:
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</a></th><td>Directory where Apache attempts to
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switch before dumping core</td></tr><tr><th><a href="directive-dict.html#Syntax">Syntax:
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</a></th><td>CoreDumpDirectory <em>directory</em></td></tr><tr><th><a href="directive-dict.html#Default">Default:
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</a></th><td><code>See usage for the default setting</code></td></tr><tr><th><a href="directive-dict.html#Context">Context:
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</a></th><td>server config</td></tr><tr><th><a href="directive-dict.html#Status">Status:
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</a></th><td>MPM</td></tr><tr><th><a href="directive-dict.html#Module">Module:
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</a></th><td><code class="module"><a href="../mod/worker.html">worker</a></code>, <code class="module"><a href="../mod/perchild.html">perchild</a></code>, <code class="module"><a href="../mod/prefork.html">prefork</a></code>, <code class="module"><a href="../mod/mpm_winnt.html">mpm_winnt</a></code></td></tr></table>
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<p>This controls the directory to which Apache attempts to
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switch before dumping core. The default is in the
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<code class="directive"><a href="../mod/core.html#serverroot">ServerRoot</a></code> directory, however
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since this should not be writable by the user the server runs
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as, core dumps won't normally get written. If you want a core
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dump for debugging, you can use this directive to place it in a
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different location.</p>
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</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div><div class="directive-section"><h2><a name="Group" id="Group">Group</a> <a name="group" id="group">Directive</a></h2><table class="directive"><tr><th><a href="directive-dict.html#Description">Description:
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</a></th><td>Group under which the server will answer
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requests</td></tr><tr><th><a href="directive-dict.html#Syntax">Syntax:
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</a></th><td>Group <em>unix-group</em></td></tr><tr><th><a href="directive-dict.html#Default">Default:
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</a></th><td><code>Group #-1</code></td></tr><tr><th><a href="directive-dict.html#Context">Context:
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</a></th><td>server config, virtual host</td></tr><tr><th><a href="directive-dict.html#Status">Status:
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</a></th><td>MPM</td></tr><tr><th><a href="directive-dict.html#Module">Module:
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</a></th><td><code class="module"><a href="../mod/worker.html">worker</a></code>, <code class="module"><a href="../mod/perchild.html">perchild</a></code>, <code class="module"><a href="../mod/prefork.html">prefork</a></code></td></tr></table>
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<p>The <code class="directive">Group</code> directive sets the group under
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which the server will answer requests. In order to use this
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directive, the stand-alone server must be run initially as root.
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<em>Unix-group</em> is one of:</p>
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<dl>
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<dt>A group name</dt>
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<dd>Refers to the given group by name.</dd>
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<dt># followed by a group number.</dt>
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<dd>Refers to a group by its number.</dd>
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</dl>
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<p>It is recommended that you set up a new group specifically for
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running the server. Some admins use user <code>nobody</code>,
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but this is not always possible or desirable.</p>
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<p>Note: if you start the server as a non-root user, it will
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fail to change to the specified group, and will instead
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continue to run as the group of the original user.</p>
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<p>Special note: Use of this directive in <VirtualHost> is
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no longer supported. To implement the <a href="../suexec.html">suEXEC wrapper</a> with Apache 2.0, use the
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<code class="directive"><a href="../mod/mod_suexec.html#suexecusergroup">SuexecUserGroup</a></code>
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directive. SECURITY: See <code class="directive"><a href="#user">User</a></code> for a discussion of the
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security considerations.</p>
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</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div><div class="directive-section"><h2><a name="Listen" id="Listen">Listen</a> <a name="listen" id="listen">Directive</a></h2><table class="directive"><tr><th><a href="directive-dict.html#Description">Description:
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</a></th><td>IP addresses and ports that the server
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listens to</td></tr><tr><th><a href="directive-dict.html#Syntax">Syntax:
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</a></th><td>Listen [<em>IP-address</em>:]<em>portnumber</em></td></tr><tr><th><a href="directive-dict.html#Context">Context:
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</a></th><td>server config</td></tr><tr><th><a href="directive-dict.html#Status">Status:
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</a></th><td>MPM</td></tr><tr><th><a href="directive-dict.html#Module">Module:
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</a></th><td><code class="module"><a href="../mod/worker.html">worker</a></code>, <code class="module"><a href="../mod/perchild.html">perchild</a></code>, <code class="module"><a href="../mod/prefork.html">prefork</a></code>, <code class="module"><a href="../mod/mpm_winnt.html">mpm_winnt</a></code></td></tr></table>
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<p>The <code class="directive">Listen</code> directive instructs Apache to
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listen to only specific IP addresses or ports; by default it
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responds to requests on all IP interfaces. The Listen directive is
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now a required directive. If it is not in the config file, the
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server will fail to start. This is a change from previous versions
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of Apache.</p>
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<p>The Listen directive tells the server to accept incoming
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requests on the specified port or address-and-port combination.
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If only a port number is specified, the server listens to the
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given port on all interfaces. If an IP address is given as well
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as a port, the server will listen on the given port and
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interface.</p>
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<p>Multiple Listen directives may be used to specify a number
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of addresses and ports to listen to. The server will respond to
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requests from any of the listed addresses and ports.</p>
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<p>For example, to make the server accept connections on both
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port 80 and port 8000, use:</p>
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<div class="example"><p><code>
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Listen 80<br />
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Listen 8000
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</code></p></div>
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<p>To make the server accept connections on two specified
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interfaces and port numbers, use </p>
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<div class="example"><p><code>
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Listen 192.170.2.1:80<br />
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Listen 192.170.2.5:8000
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</code></p></div>
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<p>IPv6 addresses must be surrounded in square brackets, as in the
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following example:</p>
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<div class="example"><p><code>
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Listen [fe80::a00:20ff:fea7:ccea]:80
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</code></p></div>
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<h3>See also</h3><ul><li><a href="../dns-caveats.html">DNS Issues</a></li><li><a href="../bind.html">Setting
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which addresses and ports Apache uses</a></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="ListenBackLog" id="ListenBackLog">ListenBackLog</a> <a name="listenbacklog" id="listenbacklog">Directive</a></h2><table class="directive"><tr><th><a href="directive-dict.html#Description">Description:
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</a></th><td>Maximum length of the queue of pending connections</td></tr><tr><th><a href="directive-dict.html#Syntax">Syntax:
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</a></th><td>ListenBacklog <em>backlog</em></td></tr><tr><th><a href="directive-dict.html#Default">Default:
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</a></th><td><code>ListenBacklog 511</code></td></tr><tr><th><a href="directive-dict.html#Context">Context:
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</a></th><td>server config</td></tr><tr><th><a href="directive-dict.html#Status">Status:
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</a></th><td>MPM</td></tr><tr><th><a href="directive-dict.html#Module">Module:
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</a></th><td><code class="module"><a href="../mod/worker.html">worker</a></code>, <code class="module"><a href="../mod/perchild.html">perchild</a></code>, <code class="module"><a href="../mod/prefork.html">prefork</a></code>, <code class="module"><a href="../mod/mpm_winnt.html">mpm_winnt</a></code></td></tr></table>
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<p>The maximum length of the queue of pending connections.
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Generally no tuning is needed or desired, however on some
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systems it is desirable to increase this when under a TCP SYN
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flood attack. See the backlog parameter to the
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<code>listen(2)</code> system call.</p>
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<p>This will often be limited to a smaller number by the
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operating system. This varies from OS to OS. Also note that
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many OSes do not use exactly what is specified as the backlog,
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but use a number based on (but normally larger than) what is
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set.</p>
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</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div><div class="directive-section"><h2><a name="LockFile" id="LockFile">LockFile</a> <a name="lockfile" id="lockfile">Directive</a></h2><table class="directive"><tr><th><a href="directive-dict.html#Description">Description:
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</a></th><td>Location of the accept serialization lock file</td></tr><tr><th><a href="directive-dict.html#Syntax">Syntax:
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</a></th><td>LockFile <em>filename</em></td></tr><tr><th><a href="directive-dict.html#Default">Default:
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</a></th><td><code>LockFile logs/accept.lock</code></td></tr><tr><th><a href="directive-dict.html#Context">Context:
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</a></th><td>server config</td></tr><tr><th><a href="directive-dict.html#Status">Status:
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</a></th><td>MPM</td></tr><tr><th><a href="directive-dict.html#Module">Module:
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</a></th><td><code class="module"><a href="../mod/worker.html">worker</a></code>, <code class="module"><a href="../mod/perchild.html">perchild</a></code>, <code class="module"><a href="../mod/prefork.html">prefork</a></code></td></tr></table>
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<p>The <code class="directive">LockFile</code> directive sets the path to
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the lockfile used when Apache is compiled with either
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USE_FCNTL_SERIALIZED_ACCEPT or USE_FLOCK_SERIALIZED_ACCEPT. This
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directive should normally be left at its default value. The main
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reason for changing it is if the <code>logs</code> directory is
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NFS mounted, since <strong>the lockfile must be stored on a local
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disk</strong>. The PID of the main server process is
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automatically appended to the filename.</p>
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<p><strong>SECURITY:</strong> It is best to avoid putting this
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file in a world writable directory such as
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<code>/var/tmp</code> because someone could create a denial of
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service attack and prevent the server from starting by creating
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a lockfile with the same name as the one the server will try to
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create.</p>
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</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div><div class="directive-section"><h2><a name="MaxClients" id="MaxClients">MaxClients</a> <a name="maxclients" id="maxclients">Directive</a></h2><table class="directive"><tr><th><a href="directive-dict.html#Description">Description:
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</a></th><td>Maximum number of child processes that will be created
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to serve requests</td></tr><tr><th><a href="directive-dict.html#Syntax">Syntax:
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</a></th><td>MaxClients <em>number</em></td></tr><tr><th><a href="directive-dict.html#Context">Context:
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</a></th><td>server config</td></tr><tr><th><a href="directive-dict.html#Status">Status:
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</a></th><td>MPM</td></tr><tr><th><a href="directive-dict.html#Module">Module:
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</a></th><td><code class="module"><a href="../mod/worker.html">worker</a></code>, <code class="module"><a href="../mod/prefork.html">prefork</a></code></td></tr></table>
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<p>The <code class="directive">MaxClients</code> directive sets the limit
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on the number of simultaneous requests that will be served. Any
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connection attempts over the <code class="directive">MaxClients</code>
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limit will normally be queued, up to a number based on the
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<code class="directive"><a href="#listenbacklog">ListenBacklog</a></code>
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directive. Once a child process is freed at the end of a different
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request, the connection will then be serviced.</p>
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<p>For non-threaded servers (i.e., <code class="module"><a href="../mod/prefork.html">prefork</a></code>),
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<code class="directive">MaxClients</code> translates into the maximum
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number of child processes that will be launched to serve requests.
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The default value is 256; to increase it, you must also raise
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<code class="directive"><a href="#serverlimit">ServerLimit</a></code>.</p>
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<p>For threaded servers (i.e., <code class="module"><a href="../mod/worker.html">worker</a></code>),
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<code class="directive">MaxClients</code> restricts the total
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number of threads that will be available to serve clients.
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The default value is 16 multiplied by the value of
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<code class="directive"><a href="#threadsperchild">ThreadsPerChild</a></code>.
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To increase <code class="directive">MaxClients</code> to a value
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that requires more than 16 processes, you must also
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raise <code class="directive"><a href="#serverlimit">ServerLimit</a></code>.</p>
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</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div><div class="directive-section"><h2><a name="MaxMemFree" id="MaxMemFree">MaxMemFree</a> <a name="maxmemfree" id="maxmemfree">Directive</a></h2><table class="directive"><tr><th><a href="directive-dict.html#Description">Description:
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</a></th><td>Maximum amount of memory that the main allocator is allowed
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to hold without calling free()</td></tr><tr><th><a href="directive-dict.html#Syntax">Syntax:
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</a></th><td>MaxMemFree <em>number</em></td></tr><tr><th><a href="directive-dict.html#Context">Context:
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</a></th><td>server config</td></tr><tr><th><a href="directive-dict.html#Status">Status:
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</a></th><td>MPM</td></tr><tr><th><a href="directive-dict.html#Module">Module:
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</a></th><td><code class="module"><a href="../mod/worker.html">worker</a></code>, <code class="module"><a href="../mod/prefork.html">prefork</a></code>, <code class="module"><a href="../mod/mpm_netware.html">mpm_netware</a></code></td></tr></table>
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<p>The <code class="directive">MaxMemFree</code> directive sets the
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maximum number of free Kbytes that the main allocator is allowed
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to hold without calling free(). When not set, or when set to
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zero, the threshold will be set to unlimited.</p>
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</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div><div class="directive-section"><h2><a name="MaxRequestsPerChild" id="MaxRequestsPerChild">MaxRequestsPerChild</a> <a name="maxrequestsperchild" id="maxrequestsperchild">Directive</a></h2><table class="directive"><tr><th><a href="directive-dict.html#Description">Description:
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</a></th><td>Limit on the number of requests that an individual child server
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will handle during its life</td></tr><tr><th><a href="directive-dict.html#Syntax">Syntax:
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</a></th><td>MaxRequestsPerChild <em>number</em></td></tr><tr><th><a href="directive-dict.html#Default">Default:
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</a></th><td><code>MaxRequestsPerChild 10000</code></td></tr><tr><th><a href="directive-dict.html#Context">Context:
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</a></th><td>server config</td></tr><tr><th><a href="directive-dict.html#Status">Status:
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</a></th><td>MPM</td></tr><tr><th><a href="directive-dict.html#Module">Module:
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</a></th><td><code class="module"><a href="../mod/worker.html">worker</a></code>, <code class="module"><a href="../mod/perchild.html">perchild</a></code>, <code class="module"><a href="../mod/prefork.html">prefork</a></code>, <code class="module"><a href="../mod/mpm_winnt.html">mpm_winnt</a></code></td></tr></table>
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<p>The <code class="directive">MaxRequestsPerChild</code> directive sets
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the limit on the number of requests that an individual child
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server process will handle. After
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<code class="directive">MaxRequestsPerChild</code> requests, the child
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process will die. If <code class="directive">MaxRequestsPerChild</code> is
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0, then the process will never expire.</p>
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<p>Setting <code class="directive">MaxRequestsPerChild</code> to a
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non-zero limit has two beneficial effects:</p>
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<ul>
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<li>it limits the amount of memory that process can consume
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by (accidental) memory leakage;</li>
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<li>by giving processes a finite lifetime, it helps reduce
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the number of processes when the server load reduces.</li>
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</ul>
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<p><strong>NOTE:</strong> For <em>KeepAlive</em> requests, only
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the first request is counted towards this limit. In effect, it
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changes the behavior to limit the number of
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<em>connections</em> per child.</p>
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</div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div><div class="directive-section"><h2><a name="MaxSpareThreads" id="MaxSpareThreads">MaxSpareThreads</a> <a name="maxsparethreads" id="maxsparethreads">Directive</a></h2><table class="directive"><tr><th><a href="directive-dict.html#Description">Description:
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</a></th><td>Maximum number of idle threads</td></tr><tr><th><a href="directive-dict.html#Syntax">Syntax:
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</a></th><td>MaxSpareThreads <em>number</em></td></tr><tr><th><a href="directive-dict.html#Context">Context:
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</a></th><td>server config</td></tr><tr><th><a href="directive-dict.html#Status">Status:
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</a></th><td>MPM</td></tr><tr><th><a href="directive-dict.html#Module">Module:
|
|
</a></th><td><code class="module"><a href="../mod/mpm_netware.html">mpm_netware</a></code>, <code class="module"><a href="../mod/perchild.html">perchild</a></code>, <code class="module"><a href="../mod/worker.html">worker</a></code></td></tr></table>
|
|
<p>Maximum number of idle threads. Different MPMs deal with this
|
|
directive differently.</p>
|
|
|
|
<p>For <code class="module"><a href="../mod/perchild.html">perchild</a></code> the default is
|
|
<code>MaxSpareThreads 10</code>. This MPM monitors the number of
|
|
idle threads on a per-child basis. If there are too many idle
|
|
threads in that child, the server will begin to kill threads
|
|
within that child.</p>
|
|
|
|
<p>For <code class="module"><a href="../mod/worker.html">worker</a></code> the default is
|
|
<code>MaxSpareThreads 500</code>. This MPM deals with idle threads
|
|
on a server-wide basis. If there are too many idle threads in the
|
|
server then child processes are killed until the number of idle
|
|
threads is less than this number.</p>
|
|
|
|
<p>For <code class="module"><a href="../mod/mpm_netware.html">mpm_netware</a></code> the default is
|
|
<code>MaxSpareThreads 100</code>. Since this MPM runs a
|
|
single-process, the spare thread count is also server-wide.</p>
|
|
|
|
<h3>See also</h3><ul><li><code class="directive"><a href="#minsparethreads">MinSpareThreads</a></code></li><li><code class="directive"><a href="#startservers">StartServers</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="MaxThreadsPerChild" id="MaxThreadsPerChild">MaxThreadsPerChild</a> <a name="maxthreadsperchild" id="maxthreadsperchild">Directive</a></h2><table class="directive"><tr><th><a href="directive-dict.html#Description">Description:
|
|
</a></th><td>Maximum number of threads per child process</td></tr><tr><th><a href="directive-dict.html#Syntax">Syntax:
|
|
</a></th><td>MaxThreadsPerChild <em>number</em></td></tr><tr><th><a href="directive-dict.html#Default">Default:
|
|
</a></th><td><code>MaxThreadsPerChild 64</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><code class="module"><a href="../mod/worker.html">worker</a></code>, <code class="module"><a href="../mod/perchild.html">perchild</a></code></td></tr></table>
|
|
<p>Maximum number of threads per child. For MPMs with a
|
|
variable number of threads per child, this directive sets the
|
|
maximum number of threads that will be created in each child
|
|
process. To increase this value beyond its default, it is
|
|
necessary to change the value of the compile-time define
|
|
<code>HARD_THREAD_LIMIT</code> and recompile the server.</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="MinSpareThreads" id="MinSpareThreads">MinSpareThreads</a> <a name="minsparethreads" id="minsparethreads">Directive</a></h2><table class="directive"><tr><th><a href="directive-dict.html#Description">Description:
|
|
</a></th><td>Minimum number of idle threads available to handle request
|
|
spikes</td></tr><tr><th><a href="directive-dict.html#Syntax">Syntax:
|
|
</a></th><td>MinSpareServers <em>number</em></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><code class="module"><a href="../mod/mpm_netware.html">mpm_netware</a></code>, <code class="module"><a href="../mod/perchild.html">perchild</a></code>, <code class="module"><a href="../mod/worker.html">worker</a></code></td></tr></table>
|
|
<p>Minimum number of idle threads to handle request spikes.
|
|
Different MPMs deal with this directive
|
|
differently.</p>
|
|
|
|
<p><code class="module"><a href="../mod/perchild.html">perchild</a></code> uses a default of
|
|
<code>MinSpareThreads 5</code> and monitors the number of idle
|
|
threads on a per-child basis. If there aren't enough idle threads
|
|
in that child, the server will begin to create new threads within
|
|
that child.</p>
|
|
|
|
<p><code class="module"><a href="../mod/worker.html">worker</a></code> uses a default of <code>MinSpareThreads
|
|
250</code> and deals with idle threads on a server-wide basis. If
|
|
there aren't enough idle threads in the server then child
|
|
processes are created until the number of idle threads is greater
|
|
than number.</p>
|
|
|
|
<p><code class="module"><a href="../mod/mpm_netware.html">mpm_netware</a></code> uses a default of
|
|
<code>MinSpareThreads 10</code> and, since it is a single-process
|
|
MPM, tracks this on a server-wide bases.</p>
|
|
|
|
<h3>See also</h3><ul><li><code class="directive"><a href="#maxsparethreads">MaxSpareThreads</a></code></li><li><code class="directive"><a href="#startservers">StartServers</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="NumServers" id="NumServers">NumServers</a> <a name="numservers" id="numservers">Directive</a></h2><table class="directive"><tr><th><a href="directive-dict.html#Description">Description:
|
|
</a></th><td>Total number of children alive at the same time</td></tr><tr><th><a href="directive-dict.html#Syntax">Syntax:
|
|
</a></th><td>NumServers <em>number</em></td></tr><tr><th><a href="directive-dict.html#Default">Default:
|
|
</a></th><td><code>NumServers 2</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><code class="module"><a href="../mod/perchild.html">perchild</a></code></td></tr></table>
|
|
<p>Number of children alive at the same time. MPMs that use
|
|
this directive do not dynamically create new child processes so
|
|
this number should be large enough to handle the requests for
|
|
the entire site.</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="PidFile" id="PidFile">PidFile</a> <a name="pidfile" id="pidfile">Directive</a></h2><table class="directive"><tr><th><a href="directive-dict.html#Description">Description:
|
|
</a></th><td>File where the server records the process ID
|
|
of the daemon</td></tr><tr><th><a href="directive-dict.html#Syntax">Syntax:
|
|
</a></th><td>PidFile <em>filename</em></td></tr><tr><th><a href="directive-dict.html#Default">Default:
|
|
</a></th><td><code>PidFile logs/httpd.pid</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><code class="module"><a href="../mod/worker.html">worker</a></code>, <code class="module"><a href="../mod/perchild.html">perchild</a></code>, <code class="module"><a href="../mod/prefork.html">prefork</a></code>, <code class="module"><a href="../mod/mpm_winnt.html">mpm_winnt</a></code></td></tr></table>
|
|
<p>The <code class="directive">PidFile</code> directive sets the file to
|
|
which the server records the process id of the daemon. If the
|
|
filename does not begin with a slash (/) then it is assumed to be
|
|
relative to the <code class="directive"><a href="../mod/core.html#serverroot">ServerRoot</a></code>.</p>
|
|
|
|
<div class="example"><h3>Example</h3><p><code>
|
|
PidFile /var/run/apache.pid
|
|
</code></p></div>
|
|
|
|
<p>It is often useful to be able to send the server a signal,
|
|
so that it closes and then reopens its <code class="directive"><a href="../mod/core.html#errorlog">ErrorLog</a></code> and TransferLog, and
|
|
re-reads its configuration files. This is done by sending a
|
|
SIGHUP (kill -1) signal to the process id listed in the
|
|
PidFile.</p>
|
|
|
|
<p>The PidFile is subject to the same warnings about log file
|
|
placement and <a href="../misc/security_tips.html#serverroot">security</a>.</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="ScoreBoardFile" id="ScoreBoardFile">ScoreBoardFile</a> <a name="scoreboardfile" id="scoreboardfile">Directive</a></h2><table class="directive"><tr><th><a href="directive-dict.html#Description">Description:
|
|
</a></th><td>Location of the file used to store coordination data for
|
|
the child processes</td></tr><tr><th><a href="directive-dict.html#Syntax">Syntax:
|
|
</a></th><td>ScoreBoardFile <em>file-path</em></td></tr><tr><th><a href="directive-dict.html#Default">Default:
|
|
</a></th><td><code>ScoreBoardFile logs/apache_status</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><code class="module"><a href="../mod/worker.html">worker</a></code>, <code class="module"><a href="../mod/perchild.html">perchild</a></code>, <code class="module"><a href="../mod/prefork.html">prefork</a></code></td></tr></table>
|
|
<p>Apache uses a scoreboard to communicate between its parent
|
|
and child processes. Some architectures require a file to facilitate
|
|
this communication. If the file is left unspecified, Apache first
|
|
attempts to create the scoreboard entirely in memory (using anonymous
|
|
shared memory) and, failing that, will attempt to create the file on
|
|
disk (using file-based shared memory). Specifying this directive causes
|
|
Apache to always create the file on the disk.</p>
|
|
|
|
<div class="example"><h3>Example</h3><p><code>
|
|
ScoreBoardFile /var/run/apache_status
|
|
</code></p></div>
|
|
|
|
<p>File-based shared memory is useful for third-party applications
|
|
that require direct access to the scoreboard.</p>
|
|
|
|
<p>If you use a <code class="directive">ScoreBoardFile</code> then
|
|
you may see improved speed by placing it on a RAM disk. But be
|
|
careful that you heed the same warnings about log file placement
|
|
and <a href="../misc/security_tips.html">security</a>.</p>
|
|
<h3>See also</h3><ul><li><a href="../stopping.html">Stopping and Restarting Apache</a></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="SendBufferSize" id="SendBufferSize">SendBufferSize</a> <a name="sendbuffersize" id="sendbuffersize">Directive</a></h2><table class="directive"><tr><th><a href="directive-dict.html#Description">Description:
|
|
</a></th><td>TCP buffer size</td></tr><tr><th><a href="directive-dict.html#Syntax">Syntax:
|
|
</a></th><td>SendBufferSize <em>bytes</em></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><code class="module"><a href="../mod/worker.html">worker</a></code>, <code class="module"><a href="../mod/perchild.html">perchild</a></code>, <code class="module"><a href="../mod/prefork.html">prefork</a></code>, <code class="module"><a href="../mod/mpm_winnt.html">mpm_winnt</a></code></td></tr></table>
|
|
<p>The server will set the TCP buffer size to the number of bytes
|
|
specified. Very useful to increase past standard OS defaults on
|
|
high speed high latency (<em>i.e.</em>, 100ms or so, such as
|
|
transcontinental fast pipes).</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="ServerLimit" id="ServerLimit">ServerLimit</a> <a name="serverlimit" id="serverlimit">Directive</a></h2><table class="directive"><tr><th><a href="directive-dict.html#Description">Description:
|
|
</a></th><td>Upper limit on configurable number of processes</td></tr><tr><th><a href="directive-dict.html#Syntax">Syntax:
|
|
</a></th><td>ServerLimit <em>number</em></td></tr><tr><th><a href="directive-dict.html#Default">Default:
|
|
</a></th><td><code>ServerLimit 256 (prefork), ServerLimit 16 (worker)</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><code class="module"><a href="../mod/worker.html">worker</a></code>, <code class="module"><a href="../mod/prefork.html">prefork</a></code></td></tr></table>
|
|
<p>For the <code class="module"><a href="../mod/prefork.html">prefork</a></code> MPM, this directive sets the
|
|
maximum configured value for <code class="directive"><a href="#maxclients">MaxClients</a></code> for the lifetime of the
|
|
Apache process. For the worker MPM, this directive in combination
|
|
with <code class="directive"><a href="#threadlimit">ThreadLimit</a></code> sets
|
|
the maximum configured value for <code class="directive"><a href="#maxclients">MaxClients</a></code> for the lifetime of the
|
|
Apache process. Any attempts to change this directive during a
|
|
restart will be ignored, but <code class="directive"><a href="#maxclients">MaxClients</a></code> can be modified during
|
|
a restart.</p>
|
|
|
|
<p>Special care must be taken when using this directive. If
|
|
<code class="directive">ServerLimit</code> is set to a value much higher
|
|
than necessary, extra, unused shared memory will be allocated. If
|
|
both <code class="directive">ServerLimit</code> and <code class="directive"><a href="#maxclients">MaxClients</a></code> are set to values
|
|
higher than the system can handle, Apache may not start or the
|
|
system may become unstable.</p>
|
|
|
|
<p>With the <code class="module"><a href="../mod/prefork.html">prefork</a></code> MPM, use this directive only
|
|
if you need to set <code class="directive"><a href="#maxclients">MaxClients</a></code> higher than 256.
|
|
Do not set the value of this directive any higher than what you
|
|
might want to set <code class="directive"><a href="#maxclients">MaxClients</a></code> to.</p>
|
|
|
|
<p>With the <code class="module"><a href="../mod/worker.html">worker</a></code> MPM, use this directive only
|
|
if your <code class="directive"><a href="#maxclients">MaxClients</a></code> and
|
|
<code class="directive"><a href="#threadsperchild">ThreadsPerChild</a></code>
|
|
settings require more than 16 server processes. Do not set the
|
|
value of this directive any higher than the number of server
|
|
processes required by what you may want for <code class="directive"><a href="#maxclients ">MaxClients </a></code> and <code class="directive"><a href="#threadsperchild">ThreadsPerChild</a></code>.</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="StartServers" id="StartServers">StartServers</a> <a name="startservers" id="startservers">Directive</a></h2><table class="directive"><tr><th><a href="directive-dict.html#Description">Description:
|
|
</a></th><td>Number of child server processes created at startup</td></tr><tr><th><a href="directive-dict.html#Syntax">Syntax:
|
|
</a></th><td>StartServers <em>number</em></td></tr><tr><th><a href="directive-dict.html#Default">Default:
|
|
</a></th><td><code>StartServers 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><code class="module"><a href="../mod/worker.html">worker</a></code></td></tr></table>
|
|
<p>The <code class="directive">StartServers</code> directive sets the
|
|
number of child server processes created on startup. As the number
|
|
of processes is dynamically controlled depending on the load,
|
|
there is usually little reason to adjust this parameter.</p>
|
|
<h3>See also</h3><ul><li><code class="directive"><a href="#minsparethreads">MinSpareThreads</a></code></li><li><code class="directive"><a href="#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="StartThreads" id="StartThreads">StartThreads</a> <a name="startthreads" id="startthreads">Directive</a></h2><table class="directive"><tr><th><a href="directive-dict.html#Description">Description:
|
|
</a></th><td>Nubmer of threads created on startup</td></tr><tr><th><a href="directive-dict.html#Syntax">Syntax:
|
|
</a></th><td>StartThreads <em>number</em></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><code class="module"><a href="../mod/mpm_netware.html">mpm_netware</a></code>, <code class="module"><a href="../mod/perchild.html">perchild</a></code></td></tr></table>
|
|
<p>Number of threads created on startup. As the
|
|
number of threads is dynamically controlled depending on the
|
|
load, there is usually little reason to adjust this
|
|
parameter.</p>
|
|
|
|
<p>For <code class="module"><a href="../mod/perchild.html">perchild</a></code> the default is <code>StartThreads
|
|
5</code> and this directive tracks the number of threads per
|
|
process at startup.</p>
|
|
|
|
<p>For <code class="module"><a href="../mod/mpm_netware.html">mpm_netware</a></code> the default is
|
|
<code>StartThreads 50</code> and, since there is only a single
|
|
process, this is the total number of threads created at startup to
|
|
serve requests.</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="ThreadLimit" id="ThreadLimit">ThreadLimit</a> <a name="threadlimit" id="threadlimit">Directive</a></h2><table class="directive"><tr><th><a href="directive-dict.html#Description">Description:
|
|
</a></th><td>Sets the upper limit on the configurable number of threads
|
|
per child process</td></tr><tr><th><a href="directive-dict.html#Syntax">Syntax:
|
|
</a></th><td>ThreadLimit <em>number</em></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><code class="module"><a href="../mod/mpm_winnt.html">mpm_winnt</a></code>, <code class="module"><a href="../mod/worker.html">worker</a></code></td></tr></table>
|
|
<p>This directive sets the maximum configured value for <code class="directive"><a href="#threadsperchild">ThreadsPerChild</a></code> for the lifetime
|
|
of the Apache process. Any attempts to change this directive
|
|
during a restart will be ignored, but <code class="directive"><a href="#threadsperchild">ThreadsPerChild</a></code> can be modified
|
|
during a restart up to the value of this directive.</p>
|
|
|
|
<p>Special care must be taken when using this directive. If
|
|
<code class="directive">ThreadLimit</code> is set to a value much higher
|
|
than <code class="directive"><a href="#threadsperchild">ThreadsPerChild</a></code>,
|
|
extra unused shared memory will be allocated. If both
|
|
<code class="directive">ThreadLimit</code> and <code class="directive"><a href="#threadsperchild">ThreadsPerChild</a></code> are set to values
|
|
higher than the system can handle, Apache may not start or the
|
|
system may become unstable. Do not set the value of this directive
|
|
any higher than your greatest predicted setting of <code class="directive"><a href="#threadsperchild">ThreadsPerChild</a></code> for the
|
|
current run of Apache.</p>
|
|
|
|
<p>The default value for <code class="directive">ThreadLimit</code> is
|
|
64 when used with <code class="module"><a href="../mod/worker.html">worker</a></code> and 1920 when used
|
|
with <code class="module"><a href="../mod/mpm_winnt.html">mpm_winnt</a></code>.</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="ThreadsPerChild" id="ThreadsPerChild">ThreadsPerChild</a> <a name="threadsperchild" id="threadsperchild">Directive</a></h2><table class="directive"><tr><th><a href="directive-dict.html#Description">Description:
|
|
</a></th><td>Number of threads created by each child process</td></tr><tr><th><a href="directive-dict.html#Syntax">Syntax:
|
|
</a></th><td>ThreadsPerChild <em>number</em></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><code class="module"><a href="../mod/worker.html">worker</a></code>, <code class="module"><a href="../mod/mpm_winnt.html">mpm_winnt</a></code></td></tr></table>
|
|
<p>This directive sets the number of threads created by each
|
|
child process. The child creates these threads at startup and
|
|
never creates more. If using an MPM like mpmt_winnt, where
|
|
there is only one child process, this number should be high
|
|
enough to handle the entire load of the server. If using an MPM
|
|
like worker, where there are multiple child processes, the
|
|
total number of threads should be high enough to handle the
|
|
common load on the server.</p>
|
|
|
|
<p>The default value for this directive is 25 when used with
|
|
<code class="module"><a href="../mod/worker.html">worker</a></code> and 64 when used with
|
|
<code class="module"><a href="../mod/mpm_winnt.html">mpm_winnt</a></code>.</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="User" id="User">User</a> <a name="user" id="user">Directive</a></h2><table class="directive"><tr><th><a href="directive-dict.html#Description">Description:
|
|
</a></th><td>The userid under which the server will answer
|
|
requests</td></tr><tr><th><a href="directive-dict.html#Syntax">Syntax:
|
|
</a></th><td>User <em>unix-userid</em></td></tr><tr><th><a href="directive-dict.html#Default">Default:
|
|
</a></th><td><code>User #-1</code></td></tr><tr><th><a href="directive-dict.html#Context">Context:
|
|
</a></th><td>server config, virtual host</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><code class="module"><a href="../mod/worker.html">worker</a></code>, <code class="module"><a href="../mod/perchild.html">perchild</a></code>, <code class="module"><a href="../mod/prefork.html">prefork</a></code></td></tr></table>
|
|
<p>The <code class="directive">User</code> directive sets the userid as
|
|
which the server will answer requests. In order to use this
|
|
directive, the standalone server must be run initially as
|
|
root. <em>Unix-userid</em> is one of:</p>
|
|
|
|
<dl>
|
|
<dt>A username</dt>
|
|
|
|
<dd>Refers to the given user by name.</dd>
|
|
|
|
<dt># followed by a user number.</dt>
|
|
|
|
<dd>Refers to a user by their number.</dd>
|
|
</dl>
|
|
|
|
<p>The user should have no privileges that result in it being
|
|
able to access files that are not intended to be visible to the
|
|
outside world, and similarly, the user should not be able to
|
|
execute code that is not meant for httpd requests. It is
|
|
recommended that you set up a new user and group specifically for
|
|
running the server. Some admins use user <code>nobody</code>, but
|
|
this is not always desirable, since the <code>nobody</code> user
|
|
can have other uses on the system.</p>
|
|
|
|
<p>Notes: If you start the server as a non-root user, it will
|
|
fail to change to the lesser privileged user, and will instead
|
|
continue to run as that original user. If you do start the
|
|
server as root, then it is normal for the parent process to
|
|
remain running as root.</p>
|
|
|
|
<p>Special note: Use of this directive in <code class="directive"><a href="../mod/core.html#virtualhost"><VirtualHost></a></code> is no longer supported. To
|
|
configure your server for <a href="mod_suexec.html">suexec</a> use
|
|
<code class="directive"><a href="../mod/mod_suexec.html#suexecusergroup">SuexecUserGroup</a></code>.</p>
|
|
|
|
<div class="note"><h3>Security</h3> <p>Don't set <code class="directive">User</code>
|
|
(or <code class="directive"><a href="#group">Group</a></code>) to
|
|
<code>root</code> unless you know exactly what you are doing, and what
|
|
the dangers are.</p></div>
|
|
</div></div><div id="footer"><p class="apache">Maintained by the <a href="http://httpd.apache.org/docs-project/">Apache HTTP Server Documentation Project</a></p><p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="../faq/">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p></div></body></html> |