mpm_common.html.en

apache的软件linux版本

    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 child processes that will be created
to serve requests</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 limit has two beneficial effects:</p>

    <ul>
      <li>it limits the amount of memory that process can consume
      by (accidental) memory leakage;</li>

      <li>by giving processes a finite lifetime, it helps reduce
      the number of processes when the server load reduces.</li>
    </ul>

    <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">