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b0fb330a8581c8bfab5e523084f9f39264a52b12gstein<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>
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f4c310fd2555c6faca1f980f00b161eadb089023gstein<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 2.3</a> > <a href="./">Modules</a></div>
1f6e6566a4ce31a0b95d5400c36d0aaff7a6e94agstein<div id="preamble"><h1>Apache MPM Common Directives</h1>
2fc50921b88defeb7127985dfe4b4130175e069ejwoolley<p><span>Available Languages: </span><a href="/de/mod/mpm_common.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> |
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cccd31fa4a72fe23cc3249c06db181b274a55a69gstein<table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>A collection of directives that are implemented by
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="module-dict.html#Status">Status:</a></th><td>MPM</td></tr></table>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<div id="quickview"><h3 class="directives">Directives</h3>
1a9d922232824a7cc008d4f74e48bd82adf5bdedgstein<li><img alt="" src="/images/down.gif" /> <a href="#coredumpdirectory">CoreDumpDirectory</a></li>
f5ec9b038bb9db933072ba2c0a8e7bb2a3cedbdagstein<li><img alt="" src="/images/down.gif" /> <a href="#enableexceptionhook">EnableExceptionHook</a></li>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<li><img alt="" src="/images/down.gif" /> <a href="#gracefulshutdowntimeout">GracefulShutdownTimeout</a></li>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<li><img alt="" src="/images/down.gif" /> <a href="#listen">Listen</a></li>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<li><img alt="" src="/images/down.gif" /> <a href="#listenbacklog">ListenBackLog</a></li>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<li><img alt="" src="/images/down.gif" /> <a href="#maxclients">MaxClients</a></li>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<li><img alt="" src="/images/down.gif" /> <a href="#maxmemfree">MaxMemFree</a></li>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<li><img alt="" src="/images/down.gif" /> <a href="#maxrequestsperchild">MaxRequestsPerChild</a></li>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<li><img alt="" src="/images/down.gif" /> <a href="#maxsparethreads">MaxSpareThreads</a></li>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<li><img alt="" src="/images/down.gif" /> <a href="#minsparethreads">MinSpareThreads</a></li>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<li><img alt="" src="/images/down.gif" /> <a href="#pidfile">PidFile</a></li>
1ccd992d37d62c8cb2056126f2234f64ec189bfddougm<li><img alt="" src="/images/down.gif" /> <a href="#receivebuffersize">ReceiveBufferSize</a></li>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<li><img alt="" src="/images/down.gif" /> <a href="#scoreboardfile">ScoreBoardFile</a></li>
1ccd992d37d62c8cb2056126f2234f64ec189bfddougm<li><img alt="" src="/images/down.gif" /> <a href="#sendbuffersize">SendBufferSize</a></li>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<li><img alt="" src="/images/down.gif" /> <a href="#serverlimit">ServerLimit</a></li>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<li><img alt="" src="/images/down.gif" /> <a href="#startservers">StartServers</a></li>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<li><img alt="" src="/images/down.gif" /> <a href="#startthreads">StartThreads</a></li>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<li><img alt="" src="/images/down.gif" /> <a href="#threadlimit">ThreadLimit</a></li>
52c1d304b1bd8e05da40a7cded2ecb9f0ba614c5gstein<li><img alt="" src="/images/down.gif" /> <a href="#threadsperchild">ThreadsPerChild</a></li>
52c1d304b1bd8e05da40a7cded2ecb9f0ba614c5gstein<li><img alt="" src="/images/down.gif" /> <a href="#threadstacksize">ThreadStackSize</a></li>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<div class="directive-section"><h2><a name="CoreDumpDirectory" id="CoreDumpDirectory">CoreDumpDirectory</a> <a name="coredumpdirectory" id="coredumpdirectory">Directive</a></h2>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Directory where Apache attempts to
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CoreDumpDirectory <var>directory</var></code></td></tr>
707ecf9559338ec06b24334bc9abcca670325cc4gstein<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>See usage for the default setting</code></td></tr>
707ecf9559338ec06b24334bc9abcca670325cc4gstein<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
707ecf9559338ec06b24334bc9abcca670325cc4gstein<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>MPM</td></tr>
707ecf9559338ec06b24334bc9abcca670325cc4gstein<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/prefork.html">prefork</a></code>, <code class="module"><a href="/mod/worker.html">worker</a></code></td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein <p>This controls the directory to which Apache attempts to
f4c310fd2555c6faca1f980f00b161eadb089023gstein switch before dumping core. If your operating system is configured to
f4c310fd2555c6faca1f980f00b161eadb089023gstein create core files in the working directory of the crashing process,
f4c310fd2555c6faca1f980f00b161eadb089023gstein <code class="directive">CoreDumpDirectory</code> is necessary to change working
707ecf9559338ec06b24334bc9abcca670325cc4gstein directory from the default <code class="directive"><a href="/mod/core.html#serverroot">ServerRoot</a></code>
707ecf9559338ec06b24334bc9abcca670325cc4gstein directory, which should not be writable by the user the server runs as.</p>
707ecf9559338ec06b24334bc9abcca670325cc4gstein <p>If you want a core dump for debugging, you can use this directive to
707ecf9559338ec06b24334bc9abcca670325cc4gstein place it in a different location. This directive has no effect if your
707ecf9559338ec06b24334bc9abcca670325cc4gstein operating system is not configured to write core files to the working directory
707ecf9559338ec06b24334bc9abcca670325cc4gstein of the crashing processes.</p>
707ecf9559338ec06b24334bc9abcca670325cc4gstein <p>If Apache starts as root and switches to another user, the
707ecf9559338ec06b24334bc9abcca670325cc4gstein Linux kernel <em>disables</em> core dumps even if the directory is
707ecf9559338ec06b24334bc9abcca670325cc4gstein writable for the process. Apache (2.0.46 and later) reenables core dumps
707ecf9559338ec06b24334bc9abcca670325cc4gstein on Linux 2.4 and beyond, but only if you explicitly configure a <code class="directive">CoreDumpDirectory</code>.</p>
707ecf9559338ec06b24334bc9abcca670325cc4gstein <p><code class="directive">CoreDumpDirectory</code> processing only occurs for
707ecf9559338ec06b24334bc9abcca670325cc4gstein a select set of fatal signals: SIGFPE, SIGILL, SIGABORT,
707ecf9559338ec06b24334bc9abcca670325cc4gstein SIGSEGV, and SIGBUS.</p>
707ecf9559338ec06b24334bc9abcca670325cc4gstein <p>On some operating systems, SIGQUIT also results in a core dump but
707ecf9559338ec06b24334bc9abcca670325cc4gstein does not go through <code class="directive">CoreDumpDirectory</code> or
707ecf9559338ec06b24334bc9abcca670325cc4gstein <code class="directive">EnableExceptionHook</code> processing, so the core
f4c310fd2555c6faca1f980f00b161eadb089023gstein location is dictated entirely by the operating system.</p>
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<div class="directive-section"><h2><a name="EnableExceptionHook" id="EnableExceptionHook">EnableExceptionHook</a> <a name="enableexceptionhook" id="enableexceptionhook">Directive</a></h2>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables a hook that runs exception handlers
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>EnableExceptionHook On|Off</code></td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>EnableExceptionHook Off</code></td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>MPM</td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Module">Module:</a></th><td><code class="module"><a href="/mod/prefork.html">prefork</a></code>, <code class="module"><a href="/mod/worker.html">worker</a></code></td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in version 2.0.49 and later</td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein <p>For safety reasons this directive is only available if the server was
f4c310fd2555c6faca1f980f00b161eadb089023gstein configured with the <code>--enable-exception-hook</code> option. It
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe enables a hook that allows external modules to plug in and do something
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe after a child crashed.</p>
f4c310fd2555c6faca1f980f00b161eadb089023gstein <p>There are already two modules, <code>mod_whatkilledus</code> and
0b1895a2cd5b4a9450709abdb7ae9974908f9382gstein <code>mod_backtrace</code> that make use of this hook. Please have a
0b1895a2cd5b4a9450709abdb7ae9974908f9382gstein look at Jeff Trawick's <a href="http://www.apache.org/~trawick/exception_hook.html">EnableExceptionHook site</a> for more information about these.</p>
0b1895a2cd5b4a9450709abdb7ae9974908f9382gstein<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
0b1895a2cd5b4a9450709abdb7ae9974908f9382gstein<div class="directive-section"><h2><a name="GracefulShutdownTimeout" id="GracefulShutdownTimeout">GracefulShutdownTimeout</a> <a name="gracefulshutdowntimeout" id="gracefulshutdowntimeout">Directive</a></h2>
0b1895a2cd5b4a9450709abdb7ae9974908f9382gstein<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Specify a timeout after which a gracefully shutdown server
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>GracefulShutDownTimeout <var>seconds</var></code></td></tr>
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>GracefulShutDownTimeout 0</code></td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>MPM</td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Module">Module:</a></th><td><code class="module"><a href="/mod/prefork.html">prefork</a></code>, <code class="module"><a href="/mod/worker.html">worker</a></code>, <code class="module"><a href="/mod/event.html">event</a></code></td></tr>
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in version 2.2 and later</td></tr>
0b1895a2cd5b4a9450709abdb7ae9974908f9382gstein <p>The <code class="directive">GracefulShutdownTimeout</code> specifies
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein how many seconds after receiving a "graceful-stop" signal, a
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein server should continue to run, handling the existing connections.</p>
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein <p>Setting this value to zero means that the server will wait
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein indefinitely until all remaining requests have been fully served.</p>
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein<div class="directive-section"><h2><a name="Listen" id="Listen">Listen</a> <a name="listen" id="listen">Directive</a></h2>
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>IP addresses and ports that the server
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Listen [<var>IP-address</var>:]<var>portnumber</var> [<var>protocol</var>]</code></td></tr>
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>MPM</td></tr>
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein<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/mpm_winnt.html">mpm_winnt</a></code>, <code class="module"><a href="/mod/mpmt_os2.html">mpmt_os2</a></code>, <code class="module"><a href="/mod/prefork.html">prefork</a></code>, <code class="module"><a href="/mod/worker.html">worker</a></code>, <code class="module"><a href="/mod/event.html">event</a></code></td></tr>
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Required directive since Apache 2.0<br />
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gsteinThe <var>protocol</var> argument was added in 2.1.5</td></tr>
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein <p>The <code class="directive">Listen</code> directive instructs Apache to
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein listen to only specific IP addresses or ports; by default it
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein responds to requests on all IP interfaces. <code class="directive">Listen</code>
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein is now a required directive. If it is not in the config file, the
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein server will fail to start. This is a change from previous versions
0b1895a2cd5b4a9450709abdb7ae9974908f9382gstein of Apache.</p>
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein <p>The <code class="directive">Listen</code> directive tells the server to
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein accept incoming requests on the specified port or address-and-port
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein combination. If only a port number is specified, the server listens to
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein the given port on all interfaces. If an IP address is given as well
956f4b1551215610a57f3b52822dbac6f41a8aa9gstein as a port, the server will listen on the given port and
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein interface.</p>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe <p>Multiple <code class="directive">Listen</code> directives may be used to
f4c310fd2555c6faca1f980f00b161eadb089023gstein specify a number of addresses and ports to listen to. The server will
f4c310fd2555c6faca1f980f00b161eadb089023gstein respond to requests from any of the listed addresses and ports.</p>
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein <p>For example, to make the server accept connections on both
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein port 80 and port 8000, use:</p>
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein Listen 80<br />
0e8fe062a6ec71b4207d1a125ee6b44b7fd30857gstein Listen 8000
f4c310fd2555c6faca1f980f00b161eadb089023gstein <p>To make the server accept connections on two specified
1ccd992d37d62c8cb2056126f2234f64ec189bfddougm interfaces and port numbers, use </p>
f4c310fd2555c6faca1f980f00b161eadb089023gstein Listen 192.170.2.1:80<br />
f4c310fd2555c6faca1f980f00b161eadb089023gstein Listen 192.170.2.5:8000
9ec6440fdeb81f04905959293b381ebbfa3114c2jorton <p>IPv6 addresses must be surrounded in square brackets, as in the
9ec6440fdeb81f04905959293b381ebbfa3114c2jorton following example:</p>
f94aab38f6ee899f463f0118ea395291f7c5b4cegstein Listen [2001:db8::a00:20ff:fea7:ccea]:80
707ecf9559338ec06b24334bc9abcca670325cc4gstein <p>The optional <var>protocol</var> argument is not required for most
707ecf9559338ec06b24334bc9abcca670325cc4gstein configurations. If not specified, <code>https</code> is the default for
707ecf9559338ec06b24334bc9abcca670325cc4gstein port 443 and <code>http</code> the default for all other ports. The
f4c310fd2555c6faca1f980f00b161eadb089023gstein protocol is used to determine which module should handle a request, and
f4c310fd2555c6faca1f980f00b161eadb089023gstein to apply protocol specific optimizations with the
f4c310fd2555c6faca1f980f00b161eadb089023gstein <code class="directive"><a href="/mod/core.html#acceptfilter">AcceptFilter</a></code> directive.</p>
f4c310fd2555c6faca1f980f00b161eadb089023gstein <p>You only need to set the protocol if you are running on non-standard
1ccd992d37d62c8cb2056126f2234f64ec189bfddougm ports. For example, running an <code>https</code> site on port 8443:</p>
f4c310fd2555c6faca1f980f00b161eadb089023gstein Listen 192.170.2.1:8443 https
f4c310fd2555c6faca1f980f00b161eadb089023gstein Multiple <code class="directive">Listen</code> directives for the same ip
f4c310fd2555c6faca1f980f00b161eadb089023gstein address and port will result in an <code>Address already in use</code>
f4c310fd2555c6faca1f980f00b161eadb089023gstein error message.
f4c310fd2555c6faca1f980f00b161eadb089023gstein<li><a href="/bind.html">Setting which addresses and ports Apache
f4c310fd2555c6faca1f980f00b161eadb089023gstein<li><a href="http://wiki.apache.org/httpd/CouldNotBindToAddress">Further
f4c310fd2555c6faca1f980f00b161eadb089023gsteindiscussion of the <code>Address already in use</code> error message,
2f40d5ac42ba2e7a8043eca56b5f5d8dce101f94wrowe<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<div class="directive-section"><h2><a name="ListenBackLog" id="ListenBackLog">ListenBackLog</a> <a name="listenbacklog" id="listenbacklog">Directive</a></h2>
2f40d5ac42ba2e7a8043eca56b5f5d8dce101f94wrowe<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maximum length of the queue of pending connections</td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ListenBacklog <var>backlog</var></code></td></tr>
2f40d5ac42ba2e7a8043eca56b5f5d8dce101f94wrowe<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ListenBacklog 511</code></td></tr>
2f40d5ac42ba2e7a8043eca56b5f5d8dce101f94wrowe<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
2f40d5ac42ba2e7a8043eca56b5f5d8dce101f94wrowe<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>MPM</td></tr>
2f40d5ac42ba2e7a8043eca56b5f5d8dce101f94wrowe<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/mpm_winnt.html">mpm_winnt</a></code>, <code class="module"><a href="/mod/mpmt_os2.html">mpmt_os2</a></code>, <code class="module"><a href="/mod/prefork.html">prefork</a></code>, <code class="module"><a href="/mod/worker.html">worker</a></code></td></tr>
2f40d5ac42ba2e7a8043eca56b5f5d8dce101f94wrowe <p>The maximum length of the queue of pending connections.
2f40d5ac42ba2e7a8043eca56b5f5d8dce101f94wrowe Generally no tuning is needed or desired, however on some
2f40d5ac42ba2e7a8043eca56b5f5d8dce101f94wrowe systems it is desirable to increase this when under a TCP SYN
2f40d5ac42ba2e7a8043eca56b5f5d8dce101f94wrowe flood attack. See the backlog parameter to the
2f40d5ac42ba2e7a8043eca56b5f5d8dce101f94wrowe <p>This will often be limited to a smaller number by the
2f40d5ac42ba2e7a8043eca56b5f5d8dce101f94wrowe operating system. This varies from OS to OS. Also note that
e8f95a682820a599fe41b22977010636be5c2717jim many OSes do not use exactly what is specified as the backlog,
2f40d5ac42ba2e7a8043eca56b5f5d8dce101f94wrowe but use a number based on (but normally larger than) what is
2f40d5ac42ba2e7a8043eca56b5f5d8dce101f94wrowe<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
2f40d5ac42ba2e7a8043eca56b5f5d8dce101f94wrowe<div class="directive-section"><h2><a name="MaxClients" id="MaxClients">MaxClients</a> <a name="maxclients" id="maxclients">Directive</a></h2>
2f40d5ac42ba2e7a8043eca56b5f5d8dce101f94wrowe<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maximum number of connections that will be processed
2f40d5ac42ba2e7a8043eca56b5f5d8dce101f94wrowe<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxClients <var>number</var></code></td></tr>
2f40d5ac42ba2e7a8043eca56b5f5d8dce101f94wrowe<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>See usage for details</code></td></tr>
2f40d5ac42ba2e7a8043eca56b5f5d8dce101f94wrowe<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
2f40d5ac42ba2e7a8043eca56b5f5d8dce101f94wrowe<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>MPM</td></tr>
2f40d5ac42ba2e7a8043eca56b5f5d8dce101f94wrowe<tr><th><a href="directive-dict.html#Module">Module:</a></th><td><code class="module"><a href="/mod/prefork.html">prefork</a></code>, <code class="module"><a href="/mod/worker.html">worker</a></code></td></tr>
2f40d5ac42ba2e7a8043eca56b5f5d8dce101f94wrowe <p>The <code class="directive">MaxClients</code> directive sets the limit
cc8241a7ee9815575a267e13eff62b6fddf1fe58gstein on the number of simultaneous requests that will be served. Any
cc8241a7ee9815575a267e13eff62b6fddf1fe58gstein connection attempts over the <code class="directive">MaxClients</code>
cc8241a7ee9815575a267e13eff62b6fddf1fe58gstein limit will normally be queued, up to a number based on the
f4c310fd2555c6faca1f980f00b161eadb089023gstein <code class="directive"><a href="#listenbacklog">ListenBacklog</a></code>
f4c310fd2555c6faca1f980f00b161eadb089023gstein directive. Once a child process is freed at the end of a different
cc8241a7ee9815575a267e13eff62b6fddf1fe58gstein request, the connection will then be serviced.</p>
f4c310fd2555c6faca1f980f00b161eadb089023gstein <p>For non-threaded servers (<em>i.e.</em>, <code class="module"><a href="/mod/prefork.html">prefork</a></code>),
f4c310fd2555c6faca1f980f00b161eadb089023gstein <code class="directive">MaxClients</code> translates into the maximum
f4c310fd2555c6faca1f980f00b161eadb089023gstein number of child processes that will be launched to serve requests.
f4c310fd2555c6faca1f980f00b161eadb089023gstein The default value is <code>256</code>; to increase it, you must also raise
1ccd992d37d62c8cb2056126f2234f64ec189bfddougm <code class="directive"><a href="#serverlimit">ServerLimit</a></code>.</p>
01e8aca9299a0b872414c24c8b7724d6f88ae665ianh <p>For threaded and hybrid servers (<em>e.g.</em> <code class="module"><a href="/mod/event.html">event</a></code>
e8f95a682820a599fe41b22977010636be5c2717jim or <code class="module"><a href="/mod/worker.html">worker</a></code>) <code class="directive">MaxClients</code> restricts
f71d4ec448449837beefe21cf7c9f8d9b6bd4654gstein the total number of threads that will be available to serve clients.
93ef028b3ac7dc86ec72204233b9d99c69587c54striker For hybrid MPMs the default value is <code>16</code> (<code class="directive"><a href="#serverlimit">ServerLimit</a></code>) multiplied by the value of
f4c310fd2555c6faca1f980f00b161eadb089023gstein <code>25</code> (<code class="directive"><a href="#threadsperchild">ThreadsPerChild</a></code>). Therefore, to increase <code class="directive">MaxClients</code> to a value that requires more than 16 processes,
f4c310fd2555c6faca1f980f00b161eadb089023gstein you must also raise <code class="directive"><a href="#serverlimit">ServerLimit</a></code>.</p>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<div class="directive-section"><h2><a name="MaxMemFree" id="MaxMemFree">MaxMemFree</a> <a name="maxmemfree" id="maxmemfree">Directive</a></h2>
f71d4ec448449837beefe21cf7c9f8d9b6bd4654gstein<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maximum amount of memory that the main allocator is allowed
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxMemFree <var>KBytes</var></code></td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxMemFree 0</code></td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>MPM</td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<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/prefork.html">prefork</a></code>, <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>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe <p>The <code class="directive">MaxMemFree</code> directive sets the
10a4cdd68ef1ca0e54af296fe1d08ac00150c90bwrowe maximum number of free Kbytes that the main allocator is allowed
10a4cdd68ef1ca0e54af296fe1d08ac00150c90bwrowe to hold without calling <code>free()</code>. When not set, or when set
f71d4ec448449837beefe21cf7c9f8d9b6bd4654gstein to zero, the threshold will be set to unlimited.</p>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
7f69a90d847f08a86f9909c2c5129408697a9600jorton<div class="directive-section"><h2><a name="MaxRequestsPerChild" id="MaxRequestsPerChild">MaxRequestsPerChild</a> <a name="maxrequestsperchild" id="maxrequestsperchild">Directive</a></h2>
7f69a90d847f08a86f9909c2c5129408697a9600jorton<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Limit on the number of requests that an individual child server
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxRequestsPerChild <var>number</var></code></td></tr>
1ccd992d37d62c8cb2056126f2234f64ec189bfddougm<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRequestsPerChild 10000</code></td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>MPM</td></tr>
7f69a90d847f08a86f9909c2c5129408697a9600jorton<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/mpm_winnt.html">mpm_winnt</a></code>, <code class="module"><a href="/mod/mpmt_os2.html">mpmt_os2</a></code>, <code class="module"><a href="/mod/prefork.html">prefork</a></code>, <code class="module"><a href="/mod/worker.html">worker</a></code></td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein <p>The <code class="directive">MaxRequestsPerChild</code> directive sets
f4c310fd2555c6faca1f980f00b161eadb089023gstein the limit on the number of requests that an individual child
f4c310fd2555c6faca1f980f00b161eadb089023gstein server process will handle. After
1ccd992d37d62c8cb2056126f2234f64ec189bfddougm <code class="directive">MaxRequestsPerChild</code> requests, the child
1ccd992d37d62c8cb2056126f2234f64ec189bfddougm process will die. If <code class="directive">MaxRequestsPerChild</code> is
9ec6440fdeb81f04905959293b381ebbfa3114c2jorton <code>0</code>, then the process will never expire.</p>
f4c310fd2555c6faca1f980f00b161eadb089023gstein <p>The default value for <code class="module"><a href="/mod/mpm_netware.html">mpm_netware</a></code> and
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe <code class="module"><a href="/mod/mpm_winnt.html">mpm_winnt</a></code> is <code>0</code>.</p>
7f69a90d847f08a86f9909c2c5129408697a9600jorton <p>Setting <code class="directive">MaxRequestsPerChild</code> to a
7f69a90d847f08a86f9909c2c5129408697a9600jorton non-zero value limits the amount of memory that process can consume
ebf7895684796436b808025426cbfab96d57910dnd by (accidental) memory leakage.</p>
7f69a90d847f08a86f9909c2c5129408697a9600jorton <p>For <code class="directive"><a href="/mod/core.html#keepalive">KeepAlive</a></code> requests, only
ebf7895684796436b808025426cbfab96d57910dnd the first request is counted towards this limit. In effect, it
7f69a90d847f08a86f9909c2c5129408697a9600jorton changes the behavior to limit the number of <em>connections</em> per
7f69a90d847f08a86f9909c2c5129408697a9600jorton<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
7f69a90d847f08a86f9909c2c5129408697a9600jorton<div class="directive-section"><h2><a name="MaxSpareThreads" id="MaxSpareThreads">MaxSpareThreads</a> <a name="maxsparethreads" id="maxsparethreads">Directive</a></h2>
7f69a90d847f08a86f9909c2c5129408697a9600jorton<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Maximum number of idle threads</td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxSpareThreads <var>number</var></code></td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>See usage for details</code></td></tr>
e8f95a682820a599fe41b22977010636be5c2717jim<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>MPM</td></tr>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<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/mpmt_os2.html">mpmt_os2</a></code>, <code class="module"><a href="/mod/worker.html">worker</a></code></td></tr>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe <p>Maximum number of idle threads. Different MPMs deal with this
f4c310fd2555c6faca1f980f00b161eadb089023gstein directive differently.</p>
f4c310fd2555c6faca1f980f00b161eadb089023gstein <p>For <code class="module"><a href="/mod/worker.html">worker</a></code>, the default is
e8f95a682820a599fe41b22977010636be5c2717jim <code>MaxSpareThreads 250</code>. This MPM deals with idle threads
7f69a90d847f08a86f9909c2c5129408697a9600jorton on a server-wide basis. If there are too many idle threads in the
9ec6440fdeb81f04905959293b381ebbfa3114c2jorton server then child processes are killed until the number of idle
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe threads is less than this number.</p>
9ec6440fdeb81f04905959293b381ebbfa3114c2jorton <p>For <code class="module"><a href="/mod/mpm_netware.html">mpm_netware</a></code> the default is
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe <code>MaxSpareThreads 100</code>. Since this MPM runs a
f4c310fd2555c6faca1f980f00b161eadb089023gstein single-process, the spare thread count is also server-wide.</p>
f4c310fd2555c6faca1f980f00b161eadb089023gstein <p><code class="module"><a href="/mod/mpmt_os2.html">mpmt_os2</a></code> works
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe similar to <code class="module"><a href="/mod/mpm_netware.html">mpm_netware</a></code>. For
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe <code class="module"><a href="/mod/mpmt_os2.html">mpmt_os2</a></code> the default value is <code>10</code>.</p>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe <p>The range of the <code class="directive">MaxSpareThreads</code> value
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe is restricted. Apache will correct the given value automatically
e8f95a682820a599fe41b22977010636be5c2717jim according to the following rules:</p>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe <li><code class="module"><a href="/mod/mpm_netware.html">mpm_netware</a></code> wants the value to be greater than
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe <code class="directive"><a href="#minsparethreads">MinSpareThreads</a></code>.</li>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe <li>For <code class="module"><a href="/mod/worker.html">worker</a></code>, the value must be greater or equal
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe to the sum of <code class="directive"><a href="#minsparethreads">MinSpareThreads</a></code>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe and <code class="directive"><a href="#threadsperchild">ThreadsPerChild</a></code>.</li>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<li><code class="directive"><a href="#minsparethreads">MinSpareThreads</a></code></li>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<li><code class="directive"><a href="#startservers">StartServers</a></code></li>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<li><code class="directive"><a href="/mod/prefork.html#maxspareservers">MaxSpareServers</a></code></li>
7ac747af0cf476c2276aaf9999425e1b52bf5f64jorton<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
7ac747af0cf476c2276aaf9999425e1b52bf5f64jorton<div class="directive-section"><h2><a name="MinSpareThreads" id="MinSpareThreads">MinSpareThreads</a> <a name="minsparethreads" id="minsparethreads">Directive</a></h2>
9ec6440fdeb81f04905959293b381ebbfa3114c2jorton<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Minimum number of idle threads available to handle request
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MinSpareThreads <var>number</var></code></td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>See usage for details</code></td></tr>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>MPM</td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<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/mpmt_os2.html">mpmt_os2</a></code>, <code class="module"><a href="/mod/worker.html">worker</a></code></td></tr>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe <p>Minimum number of idle threads to handle request spikes.
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe Different MPMs deal with this directive
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe differently.</p>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe <p><code class="module"><a href="/mod/worker.html">worker</a></code> uses a default of <code>MinSpareThreads
f4c310fd2555c6faca1f980f00b161eadb089023gstein 75</code> and deals with idle threads on a server-wide basis. If
9ec6440fdeb81f04905959293b381ebbfa3114c2jorton there aren't enough idle threads in the server then child
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe processes are created until the number of idle threads is greater
f4c310fd2555c6faca1f980f00b161eadb089023gstein <p><code class="module"><a href="/mod/mpm_netware.html">mpm_netware</a></code> uses a default of
066877f1a045103acfdd376d48cdd473c33f409bdougm <code>MinSpareThreads 10</code> and, since it is a single-process
066877f1a045103acfdd376d48cdd473c33f409bdougm MPM, tracks this on a server-wide bases.</p>
da9adab0554faf94f8cc2705c2363aceacf75c46gstein <p><code class="module"><a href="/mod/mpmt_os2.html">mpmt_os2</a></code> works
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe similar to <code class="module"><a href="/mod/mpm_netware.html">mpm_netware</a></code>. For
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe <code class="module"><a href="/mod/mpmt_os2.html">mpmt_os2</a></code> the default value is <code>5</code>.</p>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<li><code class="directive"><a href="#maxsparethreads">MaxSpareThreads</a></code></li>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<li><code class="directive"><a href="#startservers">StartServers</a></code></li>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<li><code class="directive"><a href="/mod/prefork.html#minspareservers">MinSpareServers</a></code></li>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<div class="directive-section"><h2><a name="PidFile" id="PidFile">PidFile</a> <a name="pidfile" id="pidfile">Directive</a></h2>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>File where the server records the process ID
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>PidFile <var>filename</var></code></td></tr>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>PidFile logs/httpd.pid</code></td></tr>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>MPM</td></tr>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<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/mpmt_os2.html">mpmt_os2</a></code>, <code class="module"><a href="/mod/prefork.html">prefork</a></code>, <code class="module"><a href="/mod/worker.html">worker</a></code></td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein <p>The <code class="directive">PidFile</code> directive sets the file to
f4c310fd2555c6faca1f980f00b161eadb089023gstein which the server records the process id of the daemon. If the
f4c310fd2555c6faca1f980f00b161eadb089023gstein filename is not absolute then it is assumed to be relative to the
f4c310fd2555c6faca1f980f00b161eadb089023gstein <code class="directive"><a href="/mod/core.html#serverroot">ServerRoot</a></code>.</p>
f4c310fd2555c6faca1f980f00b161eadb089023gstein <p>It is often useful to be able to send the server a signal,
f4c310fd2555c6faca1f980f00b161eadb089023gstein so that it closes and then re-opens its <code class="directive"><a href="/mod/core.html#errorlog">ErrorLog</a></code> and <code class="directive"><a href="/mod/mod_log_config.html#transferlog">TransferLog</a></code>, and
f4c310fd2555c6faca1f980f00b161eadb089023gstein re-reads its configuration files. This is done by sending a
f4c310fd2555c6faca1f980f00b161eadb089023gstein SIGHUP (kill -1) signal to the process id listed in the
4c449c30215bd5e8bad122a4118f5a7b0e995472wrowe <p>The <code class="directive">PidFile</code> is subject to the same
f4c310fd2555c6faca1f980f00b161eadb089023gstein warnings about log file placement and <a href="/misc/security_tips.html#serverroot">security</a>.</p>
f4c310fd2555c6faca1f980f00b161eadb089023gstein <p>As of Apache 2, we recommended that you only use the <code class="program"><a href="/programs/apachectl.html">apachectl</a></code> script, or the init script that your OS provides,
1ccd992d37d62c8cb2056126f2234f64ec189bfddougm for (re-)starting or stopping the server.</p>
2f40d5ac42ba2e7a8043eca56b5f5d8dce101f94wrowe<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<div class="directive-section"><h2><a name="ReceiveBufferSize" id="ReceiveBufferSize">ReceiveBufferSize</a> <a name="receivebuffersize" id="receivebuffersize">Directive</a></h2>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>TCP receive buffer size</td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ReceiveBufferSize <var>bytes</var></code></td></tr>
1ccd992d37d62c8cb2056126f2234f64ec189bfddougm<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ReceiveBufferSize 0</code></td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>MPM</td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<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/mpm_winnt.html">mpm_winnt</a></code>, <code class="module"><a href="/mod/mpmt_os2.html">mpmt_os2</a></code>, <code class="module"><a href="/mod/prefork.html">prefork</a></code>, <code class="module"><a href="/mod/worker.html">worker</a></code></td></tr>
066877f1a045103acfdd376d48cdd473c33f409bdougm <p>The server will set the TCP receive buffer size to the number of
4c449c30215bd5e8bad122a4118f5a7b0e995472wrowe bytes specified.</p>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe <p>If set to the value of <code>0</code>, the server will use the
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe OS default.</p>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<div class="directive-section"><h2><a name="ScoreBoardFile" id="ScoreBoardFile">ScoreBoardFile</a> <a name="scoreboardfile" id="scoreboardfile">Directive</a></h2>
2f40d5ac42ba2e7a8043eca56b5f5d8dce101f94wrowe<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Location of the file used to store coordination data for
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ScoreBoardFile <var>file-path</var></code></td></tr>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ScoreBoardFile logs/apache_status</code></td></tr>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>MPM</td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<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/prefork.html">prefork</a></code>, <code class="module"><a href="/mod/worker.html">worker</a></code></td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein <p>Apache uses a scoreboard to communicate between its parent
f5ec9b038bb9db933072ba2c0a8e7bb2a3cedbdagstein and child processes. Some architectures require a file to facilitate
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe this communication. If the file is left unspecified, Apache first
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe attempts to create the scoreboard entirely in memory (using anonymous
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe shared memory) and, failing that, will attempt to create the file on
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe disk (using file-based shared memory). Specifying this directive causes
f4c310fd2555c6faca1f980f00b161eadb089023gstein Apache to always create the file on the disk.</p>
5646ba89a25a695006edae46de226fb57a2e6270gstein <p>File-based shared memory is useful for third-party applications
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe that require direct access to the scoreboard.</p>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe <p>If you use a <code class="directive">ScoreBoardFile</code> then
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe you may see improved speed by placing it on a RAM disk. But be
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe careful that you heed the same warnings about log file placement
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe and <a href="/misc/security_tips.html">security</a>.</p>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<div class="directive-section"><h2><a name="SendBufferSize" id="SendBufferSize">SendBufferSize</a> <a name="sendbuffersize" id="sendbuffersize">Directive</a></h2>
1ccd992d37d62c8cb2056126f2234f64ec189bfddougm<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>TCP buffer size</td></tr>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>SendBufferSize <var>bytes</var></code></td></tr>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>SendBufferSize 0</code></td></tr>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>MPM</td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<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/mpm_winnt.html">mpm_winnt</a></code>, <code class="module"><a href="/mod/mpmt_os2.html">mpmt_os2</a></code>, <code class="module"><a href="/mod/prefork.html">prefork</a></code>, <code class="module"><a href="/mod/worker.html">worker</a></code></td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein <p>Sets the server's TCP send buffer size to the number of bytes
f4c310fd2555c6faca1f980f00b161eadb089023gstein specified. It is often useful to set this past the OS's standard
f4c310fd2555c6faca1f980f00b161eadb089023gstein default value on high speed, high latency conections
f4c310fd2555c6faca1f980f00b161eadb089023gstein (<em>i.e.</em>, 100ms or so, such as transcontinental fast pipes).</p>
f4c310fd2555c6faca1f980f00b161eadb089023gstein <p>If set to the value of <code>0</code>, the server will use the
f4c310fd2555c6faca1f980f00b161eadb089023gstein default value provided by your OS.</p>
cc8241a7ee9815575a267e13eff62b6fddf1fe58gstein<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
cc8241a7ee9815575a267e13eff62b6fddf1fe58gstein<div class="directive-section"><h2><a name="ServerLimit" id="ServerLimit">ServerLimit</a> <a name="serverlimit" id="serverlimit">Directive</a></h2>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Upper limit on configurable number of processes</td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ServerLimit <var>number</var></code></td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>See usage for details</code></td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>MPM</td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Module">Module:</a></th><td><code class="module"><a href="/mod/prefork.html">prefork</a></code>, <code class="module"><a href="/mod/worker.html">worker</a></code></td></tr>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe <p>For the <code class="module"><a href="/mod/prefork.html">prefork</a></code> MPM, this directive sets the
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe maximum configured value for <code class="directive"><a href="#maxclients">MaxClients</a></code> for the lifetime of the
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe Apache process. For the <code class="module"><a href="/mod/worker.html">worker</a></code> MPM, this directive
f4c310fd2555c6faca1f980f00b161eadb089023gstein in combination with <code class="directive"><a href="#threadlimit">ThreadLimit</a></code> sets
f4c310fd2555c6faca1f980f00b161eadb089023gstein the maximum configured value for <code class="directive"><a href="#maxclients">MaxClients</a></code> for the lifetime of the
f4c310fd2555c6faca1f980f00b161eadb089023gstein Apache process. Any attempts to change this directive during a
f4c310fd2555c6faca1f980f00b161eadb089023gstein restart will be ignored, but <code class="directive"><a href="#maxclients">MaxClients</a></code> can be modified during
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe a restart.</p>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe <p>Special care must be taken when using this directive. If
f4c310fd2555c6faca1f980f00b161eadb089023gstein <code class="directive">ServerLimit</code> is set to a value much higher
f4c310fd2555c6faca1f980f00b161eadb089023gstein than necessary, extra, unused shared memory will be allocated. If
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe both <code class="directive">ServerLimit</code> and <code class="directive"><a href="#maxclients">MaxClients</a></code> are set to values
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe higher than the system can handle, Apache may not start or the
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe system may become unstable.</p>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe <p>With the <code class="module"><a href="/mod/prefork.html">prefork</a></code> MPM, use this directive only
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe if you need to set <code class="directive"><a href="#maxclients">MaxClients</a></code> higher than 256 (default).
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe Do not set the value of this directive any higher than what you
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe might want to set <code class="directive"><a href="#maxclients">MaxClients</a></code> to.</p>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe <p>With <code class="module"><a href="/mod/worker.html">worker</a></code>, use this directive only
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe if your <code class="directive"><a href="#maxclients">MaxClients</a></code> and
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe <code class="directive"><a href="#threadsperchild">ThreadsPerChild</a></code>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe settings require more than 16 server processes (default). Do not set
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe the value of this directive any higher than the number of server
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe 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>
f4c310fd2555c6faca1f980f00b161eadb089023gstein <p>There is a hard limit of <code>ServerLimit 20000</code> compiled
f4c310fd2555c6faca1f980f00b161eadb089023gstein into the server (for the <code class="module"><a href="/mod/prefork.html">prefork</a></code> MPM 200000). This is
f4c310fd2555c6faca1f980f00b161eadb089023gstein intended to avoid nasty effects caused by typos.</p>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<li><a href="/stopping.html">Stopping and Restarting Apache</a></li>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
da9adab0554faf94f8cc2705c2363aceacf75c46gstein<div class="directive-section"><h2><a name="StartServers" id="StartServers">StartServers</a> <a name="startservers" id="startservers">Directive</a></h2>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of child server processes created at startup</td></tr>
cc8241a7ee9815575a267e13eff62b6fddf1fe58gstein<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>StartServers <var>number</var></code></td></tr>
cc8241a7ee9815575a267e13eff62b6fddf1fe58gstein<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>See usage for details</code></td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>MPM</td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Module">Module:</a></th><td><code class="module"><a href="/mod/mpmt_os2.html">mpmt_os2</a></code>, <code class="module"><a href="/mod/prefork.html">prefork</a></code>, <code class="module"><a href="/mod/worker.html">worker</a></code></td></tr>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe <p>The <code class="directive">StartServers</code> directive sets the
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe number of child server processes created on startup. As the number
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe of processes is dynamically controlled depending on the load,
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe there is usually little reason to adjust this parameter.</p>
f4c310fd2555c6faca1f980f00b161eadb089023gstein <p>The default value differs from MPM to MPM. <code class="module"><a href="/mod/worker.html">worker</a></code>
da9adab0554faf94f8cc2705c2363aceacf75c46gstein defaults to <code>StartServers 3</code>; <code class="module"><a href="/mod/prefork.html">prefork</a></code>
da9adab0554faf94f8cc2705c2363aceacf75c46gstein defaults to <code>5</code>; <code class="module"><a href="/mod/mpmt_os2.html">mpmt_os2</a></code> defaults to
f4c310fd2555c6faca1f980f00b161eadb089023gstein<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<div class="directive-section"><h2><a name="StartThreads" id="StartThreads">StartThreads</a> <a name="startthreads" id="startthreads">Directive</a></h2>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of threads created on startup</td></tr>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>StartThreads <var>number</var></code></td></tr>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>See usage for details</code></td></tr>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>MPM</td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<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></td></tr>
da9adab0554faf94f8cc2705c2363aceacf75c46gstein <p>Number of threads created on startup. As the
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe number of threads is dynamically controlled depending on the
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe load, there is usually little reason to adjust this
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe parameter.</p>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe <p>For <code class="module"><a href="/mod/mpm_netware.html">mpm_netware</a></code> the default is
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe <code>StartThreads 50</code> and, since there is only a single
f4c310fd2555c6faca1f980f00b161eadb089023gstein process, this is the total number of threads created at startup to
f4c310fd2555c6faca1f980f00b161eadb089023gstein serve requests.</p>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<div class="directive-section"><h2><a name="ThreadLimit" id="ThreadLimit">ThreadLimit</a> <a name="threadlimit" id="threadlimit">Directive</a></h2>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Sets the upper limit on the configurable number of threads
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ThreadLimit <var>number</var></code></td></tr>
866b521be8a30b2798ad3c3b73de5e965edd7c2fgstein<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>See usage for details</code></td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>MPM</td></tr>
f39230a531b23d94f86a087963299bbe2e431a4agstein<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>
f39230a531b23d94f86a087963299bbe2e431a4agstein<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available for <code class="module"><a href="/mod/mpm_winnt.html">mpm_winnt</a></code> in Apache 2.0.41
f4c310fd2555c6faca1f980f00b161eadb089023gstein <p>This directive sets the maximum configured value for <code class="directive"><a href="#threadsperchild">ThreadsPerChild</a></code> for the lifetime
f4c310fd2555c6faca1f980f00b161eadb089023gstein of the Apache process. Any attempts to change this directive
f4c310fd2555c6faca1f980f00b161eadb089023gstein during a restart will be ignored, but <code class="directive"><a href="#threadsperchild">ThreadsPerChild</a></code> can be modified
f4c310fd2555c6faca1f980f00b161eadb089023gstein during a restart up to the value of this directive.</p>
f4c310fd2555c6faca1f980f00b161eadb089023gstein <p>Special care must be taken when using this directive. If
f4c310fd2555c6faca1f980f00b161eadb089023gstein <code class="directive">ThreadLimit</code> is set to a value much higher
f4c310fd2555c6faca1f980f00b161eadb089023gstein than <code class="directive"><a href="#threadsperchild">ThreadsPerChild</a></code>,
f4c310fd2555c6faca1f980f00b161eadb089023gstein extra unused shared memory will be allocated. If both
1ccd992d37d62c8cb2056126f2234f64ec189bfddougm <code class="directive">ThreadLimit</code> and <code class="directive"><a href="#threadsperchild">ThreadsPerChild</a></code> are set to values
f4c310fd2555c6faca1f980f00b161eadb089023gstein higher than the system can handle, Apache may not start or the
f4c310fd2555c6faca1f980f00b161eadb089023gstein system may become unstable. Do not set the value of this directive
ba2ad3b1bb4a729278ad8e8846d34ddd27b6551cgstein any higher than your greatest predicted setting of <code class="directive"><a href="#threadsperchild">ThreadsPerChild</a></code> for the
ba2ad3b1bb4a729278ad8e8846d34ddd27b6551cgstein current run of Apache.</p>
f4c310fd2555c6faca1f980f00b161eadb089023gstein <p>The default value for <code class="directive">ThreadLimit</code> is
f5ec9b038bb9db933072ba2c0a8e7bb2a3cedbdagstein <code>1920</code> when used with <code class="module"><a href="/mod/mpm_winnt.html">mpm_winnt</a></code> and
f4c310fd2555c6faca1f980f00b161eadb089023gstein <p>There is a hard limit of <code>ThreadLimit 20000</code> (or
f4c310fd2555c6faca1f980f00b161eadb089023gstein <code>ThreadLimit 15000</code> with <code class="module"><a href="/mod/mpm_winnt.html">mpm_winnt</a></code>)
f4c310fd2555c6faca1f980f00b161eadb089023gstein compiled into the server. This is intended to avoid nasty effects
f4c310fd2555c6faca1f980f00b161eadb089023gstein caused by typos.</p>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<div class="directive-section"><h2><a name="ThreadsPerChild" id="ThreadsPerChild">ThreadsPerChild</a> <a name="threadsperchild" id="threadsperchild">Directive</a></h2>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of threads created by each child process</td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ThreadsPerChild <var>number</var></code></td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>See usage for details</code></td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>MPM</td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<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>
f4c310fd2555c6faca1f980f00b161eadb089023gstein <p>This directive sets the number of threads created by each
f4c310fd2555c6faca1f980f00b161eadb089023gstein child process. The child creates these threads at startup and
1ccd992d37d62c8cb2056126f2234f64ec189bfddougm never creates more. If using an MPM like <code class="module"><a href="/mod/mpm_winnt.html">mpm_winnt</a></code>,
f4c310fd2555c6faca1f980f00b161eadb089023gstein where there is only one child process, this number should be high
f4c310fd2555c6faca1f980f00b161eadb089023gstein enough to handle the entire load of the server. If using an MPM
f4c310fd2555c6faca1f980f00b161eadb089023gstein like <code class="module"><a href="/mod/worker.html">worker</a></code>, where there are multiple child processes,
ba2ad3b1bb4a729278ad8e8846d34ddd27b6551cgstein the <em>total</em> number of threads should be high enough to handle
f4c310fd2555c6faca1f980f00b161eadb089023gstein the common load on the server.</p>
f4c310fd2555c6faca1f980f00b161eadb089023gstein <p>The default value for <code class="directive">ThreadsPerChild</code> is
f4c310fd2555c6faca1f980f00b161eadb089023gstein <code>64</code> when used with <code class="module"><a href="/mod/mpm_winnt.html">mpm_winnt</a></code> and
f4c310fd2555c6faca1f980f00b161eadb089023gstein<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<div class="directive-section"><h2><a name="ThreadStackSize" id="ThreadStackSize">ThreadStackSize</a> <a name="threadstacksize" id="threadstacksize">Directive</a></h2>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>The size in bytes of the stack used by threads handling
f54da7877f9e092465df38bfda142f3e71dbb7aawrowe<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ThreadStackSize <var>size</var></code></td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>65536 on NetWare; varies on other operating systems</code></td></tr>
f5ec9b038bb9db933072ba2c0a8e7bb2a3cedbdagstein<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config</td></tr>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>MPM</td></tr>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<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/mpm_winnt.html">mpm_winnt</a></code>, <code class="module"><a href="/mod/worker.html">worker</a></code></td></tr>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.1 and later</td></tr>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe <p>The <code class="directive">ThreadStackSize</code> directive sets the
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe size of the stack (for autodata) of threads which handle client
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe connections and call modules to help process those connections.
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe In most cases the operating system default for stack size is
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe reasonable, but there are some conditions where it may need to be
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe adjusted:</p>
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe <li>On platforms with a relatively small default thread stack size
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe (e.g., HP-UX), Apache may crash when using some third-party modules
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe which use a relatively large amount of autodata storage. Those
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe same modules may have worked fine on other platforms where the
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe default thread stack size is larger. This type of crash is
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe resolved by setting <code class="directive">ThreadStackSize</code> to a
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe value higher than the operating system default. This type of
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe adjustment is necessary only if the provider of the third-party
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe module specifies that it is required, or if diagnosis of an Apache
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe crash indicates that the thread stack size was too small.</li>
866b521be8a30b2798ad3c3b73de5e965edd7c2fgstein <li>On platforms where the default thread stack size is
866b521be8a30b2798ad3c3b73de5e965edd7c2fgstein significantly larger than necessary for the web server
866b521be8a30b2798ad3c3b73de5e965edd7c2fgstein configuration, a higher number of threads per child process
866b521be8a30b2798ad3c3b73de5e965edd7c2fgstein will be achievable if <code class="directive">ThreadStackSize</code> is
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe set to a value lower than the operating system default. This type
f4c310fd2555c6faca1f980f00b161eadb089023gstein of adjustment should only be made in a test environment which allows
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe the full set of web server processing can be exercised, as there
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe may be infrequent requests which require more stack to process.
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe A change in the web server configuration can invalidate the
6f15570e3adc0faf87bf55f70857028276fc9e32wrowe current <code class="directive">ThreadStackSize</code> setting.</li>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<p><span>Available Languages: </span><a href="/de/mod/mpm_common.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> |
f4c310fd2555c6faca1f980f00b161eadb089023gstein<a href="/en/mod/mpm_common.html" title="English"> en </a> |
866b521be8a30b2798ad3c3b73de5e965edd7c2fgstein<a href="/ja/mod/mpm_common.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> |
866b521be8a30b2798ad3c3b73de5e965edd7c2fgstein<a href="/tr/mod/mpm_common.html" hreflang="tr" rel="alternate" title="T�rk�e"> tr </a></p>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<p class="apache">Copyright 2010 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>
f4c310fd2555c6faca1f980f00b161eadb089023gstein<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>