apache-http-server/docs/manual/mod/mod_status.xml

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<modulesynopsis metafile="mod_status.xml.meta">

<name>mod_status</name>
<description>Provides information on server activity and
performance</description>
<status>Base</status>
<sourcefile>mod_status.c</sourcefile>
<identifier>status_module</identifier>


<summary>
    <p>The Status module allows a server administrator to find out
    how well their server is performing. A HTML page is presented
    that gives the current server statistics in an easily readable
    form. If required this page can be made to automatically
    refresh (given a compatible browser). Another page gives a
    simple machine-readable list of the current server state.</p>

    <p>The details given are:</p>

    <ul>
      <li>The number of workers serving requests</li>

      <li>The number of idle workers</li>

      <li>The status of each worker, the number of requests that
      worker has performed and the total number of bytes served by
      the worker (*)</li>

      <li>A total number of accesses and byte count served (*)</li>

      <li>The time the server was started/restarted and the time it
      has been running for</li>

      <li>Averages giving the number of requests per second, the
      number of bytes served per second and the average number of
      bytes per request (*)</li>

      <li>The current percentage CPU used by each worker and in
      total by all workers combined (*)</li>

      <li>The current hosts and requests being processed (*)</li>
    </ul>

    <p>The lines marked "(*)" are only available if
    <directive module="core">ExtendedStatus</directive>
    is <code>On</code>.  In version 2.3.6, loading mod_status will
    toggle <directive module="core">ExtendedStatus</directive> On
    by default.</p>

    <note>
      <strong>It should be noted that if <module>mod_status</module> is
      loaded into the server, its handler capability is available
      in <em>all</em> configuration files, including
      <em>per</em>-directory files (<em>e.g.</em>,
      <code>.htaccess</code>). This may have security-related
      ramifications for your site.</strong>
    </note>

</summary>

<section id="enable">
    <title>Enabling Status Support</title>

    <p>To enable status reports only for browsers from the example.com
    domain add this code to your <code>httpd.conf</code>
    configuration file</p>
<highlight language="config">
&lt;Location "/server-status"&gt;
    SetHandler server-status
    Require host example.com
&lt;/Location&gt;
</highlight>

    <p>You can now access server statistics by using a Web browser
    to access the page
    <code>http://your.server.name/server-status</code></p>
</section>

<section id="autoupdate">

    <title>Automatic Updates</title>
    <p>You can get the status page to update itself automatically if
    you have a browser that supports "refresh". Access the page
    <code>http://your.server.name/server-status?refresh=N</code> to
    refresh the page every N seconds.</p>

</section>

<section id="machinereadable">

    <title>Machine Readable Status File</title>
    <p>A machine-readable version of the status file is available by
    accessing the page
    <code>http://your.server.name/server-status?auto</code>. This
    is useful when automatically run, see the Perl program
    <code>log_server_status</code>, which you will find in the
    <code>/support</code> directory of your Apache HTTP Server installation.</p>

</section>

<section id="troubleshoot">
    <title>Using server-status to troubleshoot</title>

    <p>The <code>server-status</code> page may be used as a starting
    place for troubleshooting a situation where your server is consuming
    all available resources (CPU or memory), and you wish to identify
    which requests or clients are causing the problem.</p>

    <p>First, ensure that you have <directive
    module="core">ExtendedStatus</directive> set on, so that you can see
    the full request and client information for each child or
    thread.</p>

    <p>Now look in your process list (using <code>top</code>, or similar
    process viewing utility) to identify the specific processes that are
    the main culprits. Order the output of <code>top</code> by CPU
    usage, or memory usage, depending on what problem you're trying to
    address.</p>

    <p>Reload the <code>server-status</code> page, and look for those process
    ids, and you'll be able to see what request is being served by that
    process, for what client. Requests are transient, so you may need to
    try several times before you catch it in the act, so to speak.</p>

    <p>This process <em>should</em> give you some idea what client, or
    what type of requests, are primarily responsible for your load
    problems. Often you will identify a particular web application that
    is misbehaving, or a particular client that is attacking your
    site.</p>

</section>

</modulesynopsis>