mpm_common.html.en

Apache官方在今天放出产品系列2.2的最新版本2.2.11的源码包 最流行的HTTP服务器软件之一

<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/mpmt_os2.html">mpmt_os2</a></code>, <code class="module"><a href="../mod/prefork.html">prefork</a></code>, <code class="module"><a href="../mod/worker.html">worker</a></code></td></tr>
</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/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>
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<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></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/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>
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<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/mpm_winnt.html">mpm_winnt</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>
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<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/mpm_winnt.html">mpm_winnt</a></code>, <code class="module"><a href="../mod/worker.html">worker</a></code></td></tr>
</table>
    <p>This directive sets the 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>
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<div class="directive-section"><h2><a name="ThreadStackSize" id="ThreadStackSize">ThreadStackSize</a> <a name="threadstacksize" id="threadstacksize">Directive</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>The size in bytes of the stack used by threads handling 
client connections</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>ThreadStackSize <var>size</var></code></td></tr>
<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>65536 on NetWare; varies on other operating systems</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/mpm_netware.html">mpm_netware</a></code>, <code class="module"><a href="../mod/mpm_winnt.html">mpm_winnt</a></code>, <code class="module"><a href="../mod/worker.html">worker</a></code></td></tr>
<tr><th><a href="directive-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.1 and later</td></tr>
</table>
    <p>The <code class="directive">ThreadStackSize</code> directive sets the 
    size of the stack (for autodata) of threads which handle client
    connections and call modules to help process those connections.  
    In most cases the operating system default for stack size is 
    reasonable, but there are some conditions where it may need to be 
    adjusted:</p>

    <ul>
      <li>On platforms with a relatively small default thread stack size
      (e.g., HP-UX), Apache may crash when using some third-party modules
      which use a relatively large amount of autodata storage.  Those
      same modules may have worked fine on other platforms where the
      default thread stack size is larger.  This type of crash is
      resolved by setting <code class="directive">ThreadStackSize</code> to a 
      value higher than the operating system default.  This type of 
      adjustment is necessary only if the provider of the third-party 
      module specifies that it is required, or if diagnosis of an Apache 
      crash indicates that the thread stack size was too small.</li>

      <li>On platforms where the default thread stack size is 
      significantly larger than necessary for the web server
      configuration, a higher number of threads per child process
      will be achievable if <code class="directive">ThreadStackSize</code> is
      set to a value lower than the operating system default.  This type
      of adjustment should only be made in a test environment which allows
      the full set of web server processing can be exercised, as there
      may be infrequent requests which require more stack to process.
      A change in the web server configuration can invalidate the
      current <code class="directive">ThreadStackSize</code> setting.</li>
    </ul>

</div>
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<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/prefork.html">prefork</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