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<div id="preamble"><h1>Apache Module mod_lbmethod_bytraffic</h1>
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<p><span>Available Languages: </span><a href="../en/mod/mod_lbmethod_bytraffic.html" title="English">&nbsp;en&nbsp;</a> |
<a href="../fr/mod/mod_lbmethod_bytraffic.html" hreflang="fr" rel="alternate" title="Français">&nbsp;fr&nbsp;</a></p>
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<table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Weighted Traffic Counting load balancer scheduler algorithm for <code class="module"><a href="../mod/mod_proxy_balancer.html">mod_proxy_balancer</a></code></td></tr>
<tr><th><a href="module-dict.html#Status">Status:</a></th><td>Extension</td></tr>
<tr><th><a href="module-dict.html#ModuleIdentifier">Module Identifier:</a></th><td>lbmethod_bytraffic_module</td></tr>
<tr><th><a href="module-dict.html#SourceFile">Source File:</a></th><td>mod_lbmethod_bytraffic.c</td></tr>
<tr><th><a href="module-dict.html#Compatibility">Compatibility:</a></th><td>Split off from <code class="module"><a href="../mod/mod_proxy_balancer.html">mod_proxy_balancer</a></code> in 2.3</td></tr></table>
<h3>Summary</h3>

<p>This module does not provide any configuration directives of its own.
It requires the services of <code class="module"><a href="../mod/mod_proxy_balancer.html">mod_proxy_balancer</a></code>, and
provides the <code>bytraffic</code> load balancing method.</p>
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<div id="quickview"><a href="https://www.apache.org/foundation/contributing.html" class="badge"><img src="https://www.apache.org/images/SupportApache-small.png" alt="Support Apache!" /></a><h3>Topics</h3>
<ul id="topics">
<li><img alt="" src="../images/down.gif" /> <a href="#traffic">Weighted Traffic Counting Algorithm</a></li>
</ul><h3 class="directives">Directives</h3>
<p>This module provides no
            directives.</p>
<h3>Bugfix checklist</h3><ul class="seealso"><li><a href="https://www.apache.org/dist/httpd/CHANGES_2.4">httpd changelog</a></li><li><a href="https://bz.apache.org/bugzilla/buglist.cgi?bug_status=__open__&amp;list_id=144532&amp;product=Apache%20httpd-2&amp;query_format=specific&amp;order=changeddate%20DESC%2Cpriority%2Cbug_severity&amp;component=mod_lbmethod_bytraffic">Known issues</a></li><li><a href="https://bz.apache.org/bugzilla/enter_bug.cgi?product=Apache%20httpd-2&amp;component=mod_lbmethod_bytraffic">Report a bug</a></li></ul><h3>See also</h3>
<ul class="seealso">
<li><code class="module"><a href="../mod/mod_proxy.html">mod_proxy</a></code></li>
<li><code class="module"><a href="../mod/mod_proxy_balancer.html">mod_proxy_balancer</a></code></li>
<li><a href="#comments_section">Comments</a></li></ul></div>
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<div class="section">
<h2><a name="traffic" id="traffic">Weighted Traffic Counting Algorithm</a></h2>
    
    <p>Enabled via <code>lbmethod=bytraffic</code>, the idea behind this
    scheduler is very similar to the Request Counting method, with
    the following changes:</p>

    <p><dfn>lbfactor</dfn> is <em>how much traffic, in bytes, we want
    this worker to handle</em>. This is also a normalized value
    representing their "share" of the amount of work to be done,
    but instead of simply counting the number of requests, we take
    into account the amount of traffic this worker has either seen
    or produced.</p>

    <p>If a balancer is configured as follows:</p>

    <table><tr><th>worker</th>
        <th class="data">a</th>
        <th class="data">b</th>
        <th class="data">c</th></tr>
<tr><th>lbfactor</th>
        <td class="data">1</td>
        <td class="data">2</td>
        <td class="data">1</td></tr>
</table>

    <p>Then we mean that we want <var>b</var> to process twice the
    amount of bytes than <var>a</var> or <var>c</var> should. It does
    not necessarily mean that <var>b</var> would handle twice as
    many requests, but it would process twice the I/O. Thus, the
    size of the request and response are applied to the weighting
    and selection algorithm.</p>

    <p>Note: input and output bytes are weighted the same.</p>

</div>
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