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| <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> |
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| <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 2.0</a> > <a href="./">Modules</a></div> |
| <div id="page-content"> |
| <div class="retired"><h4>Please note</h4> |
| <p>This document refers to the <strong>2.0</strong> version of Apache httpd, which <strong>is no longer maintained</strong>. Upgrade, and refer to the current version of httpd instead, documented at:</p> |
| <ul><li><a href="http://httpd.apache.org/docs/current/">Current release version of Apache HTTP Server documentation</a></li></ul><p>You may follow <a href="http://httpd.apache.org/docs/current/mod/mpm_common.html">this link</a> to go to the current version of this document.</p></div><div id="preamble"><h1>Apache MPM Common Directives</h1> |
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| <p><span>Available Languages: </span><a href="../de/mod/mpm_common.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> | |
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| </div> |
| <table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>A collection of directives that are implemented by |
| more than one multi-processing module (MPM)</td></tr> |
| <tr><th><a href="module-dict.html#Status">Status:</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="#acceptmutex">AcceptMutex</a></li> |
| <li><img alt="" src="../images/down.gif" /> <a href="#bs2000account">BS2000Account</a></li> |
| <li><img alt="" src="../images/down.gif" /> <a href="#coredumpdirectory">CoreDumpDirectory</a></li> |
| <li><img alt="" src="../images/down.gif" /> <a href="#enableexceptionhook">EnableExceptionHook</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="#minsparethreads">MinSpareThreads</a></li> |
| <li><img alt="" src="../images/down.gif" /> <a href="#pidfile">PidFile</a></li> |
| <li><img alt="" src="../images/down.gif" /> <a href="#receivebuffersize">ReceiveBufferSize</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="AcceptMutex" id="AcceptMutex">AcceptMutex</a> <a name="acceptmutex" id="acceptmutex">Directive</a></h2> |
| <table class="directive"> |
| <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Method that Apache uses to serialize multiple children |
| accepting requests on network sockets</td></tr> |
| <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>AcceptMutex Default|<var>method</var></code></td></tr> |
| <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>AcceptMutex Default</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/leader.html">leader</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/threadpool.html">threadpool</a></code>, <code class="module"><a href="../mod/worker.html">worker</a></code></td></tr> |
| </table> |
| <p>The <code class="directive">AcceptMutex</code> directives sets the |
| method that Apache uses to serialize multiple children accepting |
| requests on network sockets. Prior to Apache 2.0, the method was |
| selectable only at compile time. The optimal method to use is |
| highly architecture and platform dependent. For further details, |
| see the <a href="../misc/perf-tuning.html">performance tuning</a> |
| documentation.</p> |
| |
| <p>If this directive is set to <code>Default</code>, then the |
| compile-time selected default will be used. Other possible |
| methods are listed below. Note that not all methods are |
| available on all platforms. If a method is specified which is |
| not available, a message will be written to the error log |
| listing the available methods.</p> |
| |
| <dl> |
| <dt><code>flock</code></dt> |
| <dd>uses the <code>flock(2)</code> system call to lock the |
| file defined by the <code class="directive"><a href="#lockfile">LockFile</a></code> directive.</dd> |
| |
| <dt><code>fcntl</code></dt> |
| <dd>uses the <code>fcntl(2)</code> system call to lock the |
| file defined by the <code class="directive"><a href="#lockfile">LockFile</a></code> directive.</dd> |
| |
| <dt><code>posixsem</code></dt> |
| <dd>uses POSIX compatible semaphores to implement the mutex.</dd> |
| |
| <dt><code>pthread</code></dt> |
| <dd>uses POSIX mutexes as implemented by the POSIX Threads |
| (PThreads) specification.</dd> |
| |
| <dt><code>sysvsem</code></dt> |
| <dd>uses SySV-style semaphores to implement the mutex.</dd> |
| </dl> |
| |
| <p>If you want to find out the compile time chosen default |
| for your system, you may set your <code class="directive"><a href="../mod/core.html#loglevel">LogLevel</a></code> to <code>debug</code>. Then the default <code class="directive">AcceptMutex</code> will be written into the <code class="directive"><a href="../mod/core.html#errorlog">ErrorLog</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="BS2000Account" id="BS2000Account">BS2000Account</a> <a name="bs2000account" id="bs2000account">Directive</a></h2> |
| <table class="directive"> |
| <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Define the non-privileged account on BS2000 |
| machines</td></tr> |
| <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>BS2000Account <var>account</var></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>, <code class="module"><a href="../mod/prefork.html">prefork</a></code></td></tr> |
| <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Only available for BS2000 machines</td></tr> |
| </table> |
| <p>The <code class="directive">BS2000Account</code> directive is available for |
| BS2000 hosts only. It must be used to define the account number for |
| the non-privileged apache server user (which was configured using the |
| <code class="directive"><a href="#user">User</a></code> directive). This is |
| required by the BS2000 POSIX subsystem (to change the underlying BS2000 |
| task environment by performing a sub-LOGON) to prevent CGI scripts |
| from accessing resources of the privileged account which started the |
| server, usually <code>SYSROOT</code>.</p> |
| |
| <div class="note"><h3>Note</h3> |
| <p>Only one <code>BS2000Account</code> directive can be used.</p> |
| </div> |
| |
| <h3>See also</h3> |
| <ul> |
| <li><a href="../platform/ebcdic.html">Apache EBCDIC port</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:</a></th><td>Directory where Apache attempts to |
| switch before dumping core</td></tr> |
| <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>CoreDumpDirectory <var>directory</var></code></td></tr> |
| <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>See usage for the default setting</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/beos.html">beos</a></code>, <code class="module"><a href="../mod/leader.html">leader</a></code>, <code class="module"><a href="../mod/mpm_winnt.html">mpm_winnt</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/threadpool.html">threadpool</a></code>, <code class="module"><a href="../mod/worker.html">worker</a></code></td></tr> |
| </table> |
| <p>This controls the directory to which Apache attempts to |
| switch before dumping core. The default is in the |
| <code class="directive"><a href="../mod/core.html#serverroot">ServerRoot</a></code> directory, however |
| since this should not be writable by the user the server runs |
| as, core dumps won't normally get written. If you want a core |
| dump for debugging, you can use this directive to place it in a |
| different location.</p> |
| |
| <div class="note"><h3>Core Dumps on Linux</h3> |
| <p>If Apache starts as root and switches to another user, the |
| Linux kernel <em>disables</em> core dumps even if the directory is |
| writable for the process. Apache (2.0.46 and later) reenables core dumps |
| on Linux 2.4 and beyond, but only if you explicitly configure a <code class="directive">CoreDumpDirectory</code>.</p> |
| </div> |
| |
| <div class="note"><h3>Core Dumps on BSD</h3> |
| <p>To enable core-dumping of suid-executables on BSD-systems (such |
| as FreeBSD), set <code>kern.sugid_coredump</code> to 1. |
| </p></div> |
| |
| |
| </div> |
| <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> |
| <div class="directive-section"><h2><a name="EnableExceptionHook" id="EnableExceptionHook">EnableExceptionHook</a> <a name="enableexceptionhook" id="enableexceptionhook">Directive</a></h2> |
| <table class="directive"> |
| <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enables a hook that runs exception handlers |
| after a crash</td></tr> |
| <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>EnableExceptionHook On|Off</code></td></tr> |
| <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>EnableExceptionHook Off</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/leader.html">leader</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/threadpool.html">threadpool</a></code>, <code class="module"><a href="../mod/worker.html">worker</a></code></td></tr> |
| <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in version 2.0.49 and later</td></tr> |
| </table> |
| <p>For safety reasons this directive is only available if the server was |
| configured with the <code>--enable-exception-hook</code> option. It |
| enables a hook that allows external modules to plug in and do something |
| after a child crashed.</p> |
| |
| <p>There are already two modules, <code>mod_whatkilledus</code> and |
| <code>mod_backtrace</code> that make use of this hook. Please have a |
| look at Jeff Trawick's <a href="http://www.apache.org/~trawick/exception_hook.html">EnableExceptionHook site</a> for more information about these.</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="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:</a></th><td>Group under which the server will answer |
| requests</td></tr> |
| <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Group <var>unix-group</var></code></td></tr> |
| <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>Group #-1</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/beos.html">beos</a></code>, <code class="module"><a href="../mod/leader.html">leader</a></code>, <code class="module"><a href="../mod/mpmt_os2.html">mpmt_os2</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/threadpool.html">threadpool</a></code>, <code class="module"><a href="../mod/worker.html">worker</a></code></td></tr> |
| <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Only valid in global server config since Apache |
| 2.0</td></tr> |
| </table> |
| <p>The <code class="directive">Group</code> directive sets the group under |
| which the server will answer requests. In order to use this |
| directive, the server must be run initially as <code>root</code>. If |
| you start the server as a non-root user, it will fail to change to the |
| specified group, and will instead continue to run as the group of the |
| original user. <var>Unix-group</var> is one of:</p> |
| |
| <dl> |
| <dt>A group name</dt> |
| <dd>Refers to the given group by name.</dd> |
| |
| <dt><code>#</code> followed by a group number.</dt> |
| <dd>Refers to a group by its number.</dd> |
| </dl> |
| |
| <div class="example"><h3>Example</h3><p><code> |
| Group www-group |
| </code></p></div> |
| |
| <p>It is recommended that you set up a new group specifically for |
| running the server. Some admins use user <code>nobody</code>, |
| but this is not always possible or desirable.</p> |
| |
| <div class="warning"><h3>Security</h3> |
| <p>Don't set <code class="directive">Group</code> (or <code class="directive"><a href="#user">User</a></code>) to <code>root</code> unless |
| you know exactly what you are doing, and what the dangers are.</p> |
| </div> |
| |
| <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 <code class="program"><a href="../programs/suexec.html">suexec</a></code> use |
| <code class="directive"><a href="../mod/mod_suexec.html#suexecusergroup">SuexecUserGroup</a></code>.</p> |
| |
| <div class="note"><h3>Note</h3> |
| <p>Although the <code class="directive">Group</code> directive is present |
| in the <code class="module"><a href="../mod/beos.html">beos</a></code> and <code class="module"><a href="../mod/mpmt_os2.html">mpmt_os2</a></code> MPMs, |
| it is actually a no-op there and only exists for compatibility |
| reasons.</p> |
| </div> |
| |
| </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:</a></th><td>IP addresses and ports that the server |
| listens to</td></tr> |
| <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>Listen [<var>IP-address</var>:]<var>portnumber</var></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/beos.html">beos</a></code>, <code class="module"><a href="../mod/leader.html">leader</a></code>, <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/perchild.html">perchild</a></code>, <code class="module"><a href="../mod/prefork.html">prefork</a></code>, <code class="module"><a href="../mod/threadpool.html">threadpool</a></code>, <code class="module"><a href="../mod/worker.html">worker</a></code></td></tr> |
| <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Required directive since Apache 2.0</td></tr> |
| </table> |
| <p>The <code class="directive">Listen</code> directive instructs Apache to |
| listen to only specific IP addresses or ports; by default it |
| responds to requests on all IP interfaces. <code class="directive">Listen</code> |
| is now a required directive. If it is not in the config file, the |
| server will fail to start. This is a change from previous versions |
| of Apache.</p> |
| |
| <p>The <code class="directive">Listen</code> directive tells the server to |
| accept incoming requests on the specified port or address-and-port |
| combination. If only a port number is specified, the server listens to |
| the given port on all interfaces. If an IP address is given as well |
| as a port, the server will listen on the given port and |
| interface.</p> |
| |
| <p>Multiple <code class="directive">Listen</code> directives may be used to |
| specify a number of addresses and ports to listen to. The server will |
| respond to requests from any of the listed addresses and ports.</p> |
| |
| <p>For example, to make the server accept connections on both |
| port 80 and port 8000, use:</p> |
| |
| <div class="example"><p><code> |
| Listen 80<br /> |
| Listen 8000 |
| </code></p></div> |
| |
| <p>To make the server accept connections on two specified |
| interfaces and port numbers, use </p> |
| |
| <div class="example"><p><code> |
| Listen 192.170.2.1:80<br /> |
| Listen 192.170.2.5:8000 |
| </code></p></div> |
| |
| <p>IPv6 addresses must be surrounded in square brackets, as in the |
| following example:</p> |
| |
| <div class="example"><p><code> |
| Listen [2001:db8::a00:20ff:fea7:ccea]:80 |
| </code></p></div> |
| |
| <div class="note"><h3>Error condition</h3> |
| Multiple <code class="directive">Listen</code> directives for the same ip |
| address and port will result in an <code>Address already in use</code> |
| error message. |
| </div> |
| |
| <h3>See also</h3> |
| <ul> |
| <li><a href="../dns-caveats.html">DNS Issues</a></li> |
| <li><a href="../bind.html">Setting 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:</a></th><td>Maximum length of the queue of pending connections</td></tr> |
| <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ListenBacklog <var>backlog</var></code></td></tr> |
| <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ListenBacklog 511</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/beos.html">beos</a></code>, <code class="module"><a href="../mod/leader.html">leader</a></code>, <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/perchild.html">perchild</a></code>, <code class="module"><a href="../mod/prefork.html">prefork</a></code>, <code class="module"><a href="../mod/threadpool.html">threadpool</a></code>, <code class="module"><a href="../mod/worker.html">worker</a></code></td></tr> |
| </table> |
| <p>The maximum length of the queue of pending connections. |
| Generally no tuning is needed or desired, however on some |
| systems it is desirable to increase this when under a TCP SYN |
| flood attack. See the backlog parameter to the |
| <code>listen(2)</code> system call.</p> |
| |
| <p>This will often be limited to a smaller number by the |
| operating system. This varies from OS to OS. Also note that |
| many OSes do not use exactly what is specified as the backlog, |
| but use a number based on (but normally larger than) what is |
| set.</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="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:</a></th><td>Location of the accept serialization lock file</td></tr> |
| <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>LockFile <var>filename</var></code></td></tr> |
| <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>LockFile logs/accept.lock</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/leader.html">leader</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/threadpool.html">threadpool</a></code>, <code class="module"><a href="../mod/worker.html">worker</a></code></td></tr> |
| </table> |
| <p>The <code class="directive">LockFile</code> directive sets the path to |
| the lockfile used when Apache is used with an <code class="directive"><a href="#acceptmutex">AcceptMutex</a></code> value of either |
| <code>fcntl</code> or <code>flock</code>. This directive should |
| normally be left at its default value. The main reason for changing |
| it is if the <code>logs</code> directory is NFS mounted, since |
| <strong>the lockfile must be stored on a local disk</strong>. The PID |
| of the main server process is automatically appended to the |
| filename.</p> |
| |
| <div class="warning"><h3>Security</h3> |
| <p>It is best to <em>avoid</em> putting this file in a world writable |
| directory such as <code>/var/tmp</code> because someone could create |
| a denial of service attack and prevent the server from starting by |
| creating a lockfile with the same name as the one the server will try |
| to create.</p> |
| </div> |
| |
| <h3>See also</h3> |
| <ul> |
| <li><code class="directive"><a href="#acceptmutex">AcceptMutex</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="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:</a></th><td>Maximum number of connections that will be processed |
| simultaneously</td></tr> |
| <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxClients <var>number</var></code></td></tr> |
| <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>See usage for details</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/beos.html">beos</a></code>, <code class="module"><a href="../mod/leader.html">leader</a></code>, <code class="module"><a href="../mod/prefork.html">prefork</a></code>, <code class="module"><a href="../mod/threadpool.html">threadpool</a></code>, <code class="module"><a href="../mod/worker.html">worker</a></code></td></tr> |
| </table> |
| <p>The <code class="directive">MaxClients</code> directive sets the limit |
| on the number of simultaneous requests that will be served. Any |
| connection attempts over the <code class="directive">MaxClients</code> |
| limit will normally be queued, up to a number based on the |
| <code class="directive"><a href="#listenbacklog">ListenBacklog</a></code> |
| directive. Once a child process is freed at the end of a different |
| request, the connection will then be serviced.</p> |
| |
| <p>For non-threaded servers (<em>i.e.</em>, <code class="module"><a href="../mod/prefork.html">prefork</a></code>), |
| <code class="directive">MaxClients</code> translates into the maximum |
| number of child processes that will be launched to serve requests. |
| The default value is <code>256</code>; to increase it, you must also raise |
| <code class="directive"><a href="#serverlimit">ServerLimit</a></code>.</p> |
| |
| <p>For threaded and hybrid servers (<em>e.g.</em> <code class="module"><a href="../mod/beos.html">beos</a></code> |
| or <code class="module"><a href="../mod/worker.html">worker</a></code>) <code class="directive">MaxClients</code> restricts |
| the total number of threads that will be available to serve clients. |
| The default value for <code class="module"><a href="../mod/beos.html">beos</a></code> is <code>50</code>. For |
| hybrid MPMs the default value is <code>16</code> (<code class="directive"><a href="#serverlimit">ServerLimit</a></code>) multiplied by the value of |
| <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, |
| you must also raise <code class="directive"><a href="#serverlimit">ServerLimit</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="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:</a></th><td>Maximum amount of memory that the main allocator is allowed |
| to hold without calling <code>free()</code></td></tr> |
| <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxMemFree <var>KBytes</var></code></td></tr> |
| <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxMemFree 0</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/beos.html">beos</a></code>, <code class="module"><a href="../mod/leader.html">leader</a></code>, <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/threadpool.html">threadpool</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> |
| </table> |
| <p>The <code class="directive">MaxMemFree</code> directive sets the |
| maximum number of free Kbytes that the main allocator is allowed |
| to hold without calling <code>free()</code>. When not set, or when set |
| to zero, the threshold will be set to unlimited.</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="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:</a></th><td>Limit on the number of requests that an individual child server |
| will handle during its life</td></tr> |
| <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxRequestsPerChild <var>number</var></code></td></tr> |
| <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MaxRequestsPerChild 10000</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/leader.html">leader</a></code>, <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/perchild.html">perchild</a></code>, <code class="module"><a href="../mod/prefork.html">prefork</a></code>, <code class="module"><a href="../mod/threadpool.html">threadpool</a></code>, <code class="module"><a href="../mod/worker.html">worker</a></code></td></tr> |
| </table> |
| <p>The <code class="directive">MaxRequestsPerChild</code> directive sets |
| the limit on the number of requests that an individual child |
| server process will handle. After |
| <code class="directive">MaxRequestsPerChild</code> requests, the child |
| process will die. If <code class="directive">MaxRequestsPerChild</code> is |
| <code>0</code>, then the process will never expire.</p> |
| |
| <div class="note"><h3>Different default values</h3> |
| <p>The default value for <code class="module"><a href="../mod/mpm_netware.html">mpm_netware</a></code> and |
| <code class="module"><a href="../mod/mpm_winnt.html">mpm_winnt</a></code> is <code>0</code>.</p> |
| </div> |
| |
| <p>Setting <code class="directive">MaxRequestsPerChild</code> to a |
| non-zero value limits the amount of memory that process can consume |
| by (accidental) memory leakage.</p> |
| |
| <div class="note"><h3>Note</h3> |
| <p>For <code class="directive"><a href="../mod/core.html#keepalive">KeepAlive</a></code> requests, only |
| the first request is counted towards this limit. In effect, it |
| changes the behavior to limit the number of <em>connections</em> per |
| child.</p> |
| </div> |
| |
| </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:</a></th><td>Maximum number of idle threads</td></tr> |
| <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MaxSpareThreads <var>number</var></code></td></tr> |
| <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>See usage for details</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/beos.html">beos</a></code>, <code class="module"><a href="../mod/leader.html">leader</a></code>, <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/perchild.html">perchild</a></code>, <code class="module"><a href="../mod/threadpool.html">threadpool</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>, <code class="module"><a href="../mod/leader.html">leader</a></code> and <code class="module"><a href="../mod/threadpool.html">threadpool</a></code> the default is <code>MaxSpareThreads 250</code>. |
| These MPMs deal 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> |
| |
| <p><code class="module"><a href="../mod/beos.html">beos</a></code> and <code class="module"><a href="../mod/mpmt_os2.html">mpmt_os2</a></code> work |
| similar to <code class="module"><a href="../mod/mpm_netware.html">mpm_netware</a></code>. The default for |
| <code class="module"><a href="../mod/beos.html">beos</a></code> is <code>MaxSpareThreads 50</code>. For |
| <code class="module"><a href="../mod/mpmt_os2.html">mpmt_os2</a></code> the default value is <code>10</code>.</p> |
| |
| <div class="note"><h3>Restrictions</h3> |
| <p>The range of the <code class="directive">MaxSpareThreads</code> value |
| is restricted. Apache will correct the given value automatically |
| according to the following rules:</p> |
| <ul> |
| <li><code class="module"><a href="../mod/perchild.html">perchild</a></code> requires <code class="directive">MaxSpareThreads</code> to be less or equal than <code class="directive"><a href="#threadlimit">ThreadLimit</a></code>.</li> |
| |
| <li><code class="module"><a href="../mod/mpm_netware.html">mpm_netware</a></code> wants the value to be greater than |
| <code class="directive"><a href="#minsparethreads">MinSpareThreads</a></code>.</li> |
| |
| <li>For <code class="module"><a href="../mod/leader.html">leader</a></code>, <code class="module"><a href="../mod/threadpool.html">threadpool</a></code> and |
| <code class="module"><a href="../mod/worker.html">worker</a></code> the value must be greater or equal than |
| the sum of <code class="directive"><a href="#minsparethreads">MinSpareThreads</a></code> |
| and <code class="directive"><a href="#threadsperchild">ThreadsPerChild</a></code>.</li> |
| </ul> |
| </div> |
| |
| <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="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><code>MinSpareThreads <var>number</var></code></td></tr> |
| <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>See usage for details</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/beos.html">beos</a></code>, <code class="module"><a href="../mod/leader.html">leader</a></code>, <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/perchild.html">perchild</a></code>, <code class="module"><a href="../mod/threadpool.html">threadpool</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. Thus, if you set <code class="directive"><a href="../mod/perchild.html#numservers">NumServers</a></code> to <code>10</code> and a <code class="directive">MinSpareThreads</code> value of <code>5</code>, you'll have |
| at least 50 idle threads on your system.</p> |
| |
| <p><code class="module"><a href="../mod/worker.html">worker</a></code>, <code class="module"><a href="../mod/leader.html">leader</a></code> and |
| <code class="module"><a href="../mod/threadpool.html">threadpool</a></code> use a default of <code>MinSpareThreads |
| 75</code> and deal 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> |
| |
| <p><code class="module"><a href="../mod/beos.html">beos</a></code> and <code class="module"><a href="../mod/mpmt_os2.html">mpmt_os2</a></code> work |
| similar to <code class="module"><a href="../mod/mpm_netware.html">mpm_netware</a></code>. The default for |
| <code class="module"><a href="../mod/beos.html">beos</a></code> is <code>MinSpareThreads 1</code>. For |
| <code class="module"><a href="../mod/mpmt_os2.html">mpmt_os2</a></code> the default value is <code>5</code>.</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="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><code>PidFile <var>filename</var></code></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/beos.html">beos</a></code>, <code class="module"><a href="../mod/leader.html">leader</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/perchild.html">perchild</a></code>, <code class="module"><a href="../mod/prefork.html">prefork</a></code>, <code class="module"><a href="../mod/threadpool.html">threadpool</a></code>, <code class="module"><a href="../mod/worker.html">worker</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 is not absolute 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 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 |
| re-reads its configuration files. This is done by sending a |
| SIGHUP (kill -1) signal to the process id listed in the |
| <code class="directive">PidFile</code>.</p> |
| |
| <p>The <code class="directive">PidFile</code> is subject to the same |
| warnings about log file placement and <a href="../misc/security_tips.html#serverroot">security</a>.</p> |
| |
| <div class="note"><h3>Note</h3> |
| <p>As of Apache 2 it is recommended to use only the <code class="program"><a href="../programs/apachectl.html">apachectl</a></code> script for (re-)starting or stopping the server.</p> |
| </div> |
| |
| </div> |
| <div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> |
| <div class="directive-section"><h2><a name="ReceiveBufferSize" id="ReceiveBufferSize">ReceiveBufferSize</a> <a name="receivebuffersize" id="receivebuffersize">Directive</a></h2> |
| <table class="directive"> |
| <tr><th><a href="directive-dict.html#Description">Description:</a></th><td>TCP receive buffer size</td></tr> |
| <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ReceiveBufferSize <var>bytes</var></code></td></tr> |
| <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>ReceiveBufferSize 0</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/beos.html">beos</a></code>, <code class="module"><a href="../mod/leader.html">leader</a></code>, <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/perchild.html">perchild</a></code>, <code class="module"><a href="../mod/prefork.html">prefork</a></code>, <code class="module"><a href="../mod/threadpool.html">threadpool</a></code>, <code class="module"><a href="../mod/worker.html">worker</a></code></td></tr> |
| </table> |
| <p>The server will set the TCP receive buffer size to the number of |
| bytes specified.</p> |
| |
| <p>If set to the value of <code>0</code>, the server will use the |
| OS default.</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><code>ScoreBoardFile <var>file-path</var></code></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/beos.html">beos</a></code>, <code class="module"><a href="../mod/leader.html">leader</a></code>, <code class="module"><a href="../mod/mpm_winnt.html">mpm_winnt</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/threadpool.html">threadpool</a></code>, <code class="module"><a href="../mod/worker.html">worker</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><code>SendBufferSize <var>bytes</var></code></td></tr> |
| <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>SendBufferSize 0</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/beos.html">beos</a></code>, <code class="module"><a href="../mod/leader.html">leader</a></code>, <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/perchild.html">perchild</a></code>, <code class="module"><a href="../mod/prefork.html">prefork</a></code>, <code class="module"><a href="../mod/threadpool.html">threadpool</a></code>, <code class="module"><a href="../mod/worker.html">worker</a></code></td></tr> |
| </table> |
| <p>The server will set the TCP send 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> |
| |
| <p>If set to the value of <code>0</code>, the server will use the |
| OS default.</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><code>ServerLimit <var>number</var></code></td></tr> |
| <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>See usage for details</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/leader.html">leader</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/threadpool.html">threadpool</a></code>, <code class="module"><a href="../mod/worker.html">worker</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 <code class="module"><a href="../mod/worker.html">worker</a></code> 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 (default). |
| 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 <code class="module"><a href="../mod/worker.html">worker</a></code>, <code class="module"><a href="../mod/leader.html">leader</a></code> and |
| <code class="module"><a href="../mod/threadpool.html">threadpool</a></code> 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 (default). 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> |
| |
| <p>With the <code class="module"><a href="../mod/perchild.html">perchild</a></code> MPM, use this directive only |
| if you need to set <code class="directive"><a href="../mod/perchild.html#numservers">NumServers</a></code> higher than 8 (default).</p> |
| |
| <div class="note"><h3>Note</h3> |
| <p>There is a hard limit of <code>ServerLimit 20000</code> compiled |
| into the server. This is intended to avoid nasty effects caused by |
| typos.</p> |
| </div> |
| |
| <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="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><code>StartServers <var>number</var></code></td></tr> |
| <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>See usage for details</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/leader.html">leader</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/threadpool.html">threadpool</a></code>, <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> |
| |
| <p>The default value differs from MPM to MPM. For |
| <code class="module"><a href="../mod/leader.html">leader</a></code>, <code class="module"><a href="../mod/threadpool.html">threadpool</a></code> and |
| <code class="module"><a href="../mod/worker.html">worker</a></code> the default is <code>StartServers 3</code>. |
| For <code class="module"><a href="../mod/prefork.html">prefork</a></code> defaults to <code>5</code> and for |
| <code class="module"><a href="../mod/mpmt_os2.html">mpmt_os2</a></code> to <code>2</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="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>Number of threads created on startup</td></tr> |
| <tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>StartThreads <var>number</var></code></td></tr> |
| <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>See usage for details</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/beos.html">beos</a></code>, <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> |
| |
| <p>For <code class="module"><a href="../mod/beos.html">beos</a></code> the default is <code>StartThreads |
| 10</code>. It also reflects 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><code>ThreadLimit <var>number</var></code></td></tr> |
| <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>See usage for details</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/leader.html">leader</a></code>, <code class="module"><a href="../mod/mpm_winnt.html">mpm_winnt</a></code>, <code class="module"><a href="../mod/perchild.html">perchild</a></code>, <code class="module"><a href="../mod/threadpool.html">threadpool</a></code>, <code class="module"><a href="../mod/worker.html">worker</a></code></td></tr> |
| <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 |
| and later</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 |
| <code>1920</code> when used with <code class="module"><a href="../mod/mpm_winnt.html">mpm_winnt</a></code> and |
| <code>64</code> when used with the others.</p> |
| |
| <div class="note"><h3>Note</h3> |
| <p>There is a hard limit of <code>ThreadLimit 20000</code> (or |
| <code>ThreadLimit 15000</code> with <code class="module"><a href="../mod/mpm_winnt.html">mpm_winnt</a></code>) |
| compiled into the server. This is intended to avoid nasty effects |
| caused by typos.</p> |
| </div> |
| |
| </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><code>ThreadsPerChild <var>number</var></code></td></tr> |
| <tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>See usage for details</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/leader.html">leader</a></code>, <code class="module"><a href="../mod/mpm_winnt.html">mpm_winnt</a></code>, <code class="module"><a href="../mod/threadpool.html">threadpool</a></code>, <code class="module"><a href="../mod/worker.html">worker</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 <code class="module"><a href="../mod/mpm_winnt.html">mpm_winnt</a></code>, |
| 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 <code class="module"><a href="../mod/worker.html">worker</a></code>, where there are multiple child processes, |
| the <em>total</em> number of threads should be high enough to handle |
| the common load on the server.</p> |
| |
| <p>The default value for <code class="directive">ThreadsPerChild</code> is |
| <code>64</code> when used with <code class="module"><a href="../mod/mpm_winnt.html">mpm_winnt</a></code> and |
| <code>25</code> when used with the others.</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><code>User <var>unix-userid</var></code></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</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/leader.html">leader</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/threadpool.html">threadpool</a></code>, <code class="module"><a href="../mod/worker.html">worker</a></code></td></tr> |
| <tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Only valid in global server config since Apache |
| 2.0</td></tr> |
| </table> |
| <p>The <code class="directive">User</code> directive sets the user ID as |
| which the server will answer requests. In order to use this |
| directive, the server must be run initially as <code>root</code>. |
| 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 <code>root</code>, |
| then it is normal for the parent process to remain running as root. |
| <var>Unix-userid</var> 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 its 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 HTTP 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> |
| |
| <div class="warning"><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> |
| |
| <p>With the <code class="module"><a href="../mod/perchild.html">perchild</a></code> MPM, which is intended to |
| server virtual hosts run under different user IDs, the |
| <code class="directive">User</code> directive defines the user ID for the |
| main server and the fallback for <code class="directive"><a href="../mod/core.html#virtualhost"><VirtualHost></a></code> sections without an |
| <code class="directive"><a href="../mod/perchild.html#assignuserid">AssignUserID</a></code> directive.</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 <code class="program"><a href="../programs/suexec.html">suexec</a></code> use |
| <code class="directive"><a href="../mod/mod_suexec.html#suexecusergroup">SuexecUserGroup</a></code>.</p> |
| |
| <div class="note"><h3>Note</h3> |
| <p>Although the <code class="directive">User</code> directive is present |
| in the <code class="module"><a href="../mod/beos.html">beos</a></code> and <code class="module"><a href="../mod/mpmt_os2.html">mpmt_os2</a></code> MPMs, |
| it is actually a no-op there and only exists for compatibility |
| reasons.</p> |
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