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| author |   hongbotian <hongbo.tianhongbo@huawei.com> | 2015-11-30 01:45:08 -0500 |
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| committer | hongbotian <hongbo.tianhongbo@huawei.com> | 2015-11-30 01:45:08 -0500 |
| commit | e8ec7aa8e38a93f5b034ac74cebce5de23710317 (patch) | |
| tree | aa031937bf856c1f8d6ad7877b8d2cb0224da5ef /rubbos/app/httpd-2.0.64/docs/manual/mod/mpm_common.html.en | |
| parent | cc40af334e619bb549038238507407866f774f8f (diff) | |
upload http
JIRA: BOTTLENECK-10
Change-Id: I7598427ff904df438ce77c2819ee48ac75ffa8da
Signed-off-by: hongbotian <hongbo.tianhongbo@huawei.com>
Diffstat (limited to 'rubbos/app/httpd-2.0.64/docs/manual/mod/mpm_common.html.en')
| -rw-r--r-- | rubbos/app/httpd-2.0.64/docs/manual/mod/mpm_common.html.en | 896 |
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diff --git a/rubbos/app/httpd-2.0.64/docs/manual/mod/mpm_common.html.en b/rubbos/app/httpd-2.0.64/docs/manual/mod/mpm_common.html.en new file mode 100644 index 00000000..5b3bbc48 --- /dev/null +++ b/rubbos/app/httpd-2.0.64/docs/manual/mod/mpm_common.html.en @@ -0,0 +1,896 @@ +<?xml version="1.0" encoding="ISO-8859-1"?> +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head><!-- + XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX + This file is generated from xml source: DO NOT EDIT + XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX + --> +<title>mpm_common - Apache HTTP Server</title> +<link href="../style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" /> +<link href="../style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" /> +<link href="../style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" /> +<link href="../images/favicon.ico" rel="shortcut icon" /></head> +<body> +<div id="page-header"> +<p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="../faq/">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p> +<p class="apache">Apache HTTP Server Version 2.0</p> +<img alt="" src="../images/feather.gif" /></div> +<div class="up"><a href="./"><img title="<-" alt="<-" src="../images/left.gif" /></a></div> +<div id="path"> +<a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs/">Documentation</a> > <a href="../">Version 2.0</a> > <a href="./">Modules</a></div> +<div id="page-content"> +<div id="preamble"><h1>Apache MPM Common Directives</h1> +<div class="toplang"> +<p><span>Available Languages: </span><a href="../de/mod/mpm_common.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> | +<a href="../en/mod/mpm_common.html" title="English"> en </a> | +<a href="../es/mod/mpm_common.html" hreflang="es" rel="alternate" title="Español"> es </a> | +<a href="../ja/mod/mpm_common.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> | +<a href="../tr/mod/mpm_common.html" hreflang="tr" rel="alternate" title="Türkçe"> tr </a></p> +</div> +<table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>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> +<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> + </div> + +</div> +</div> +<div class="bottomlang"> +<p><span>Available Languages: </span><a href="../de/mod/mpm_common.html" hreflang="de" rel="alternate" title="Deutsch"> de </a> | +<a href="../en/mod/mpm_common.html" title="English"> en </a> | +<a href="../es/mod/mpm_common.html" hreflang="es" rel="alternate" title="Español"> es </a> | +<a href="../ja/mod/mpm_common.html" hreflang="ja" rel="alternate" title="Japanese"> ja </a> | +<a href="../tr/mod/mpm_common.html" hreflang="tr" rel="alternate" title="Türkçe"> tr </a></p> +</div><div id="footer"> +<p class="apache">Copyright 2009 The Apache Software Foundation.<br />Licensed under the <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache License, Version 2.0</a>.</p> +<p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="../faq/">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p></div> +</body></html>
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