1<?xml version="1.0" encoding="ISO-8859-1"?> 2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> 3<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head><!-- 4 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX 5 This file is generated from xml source: DO NOT EDIT 6 XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX 7 --> 8<title>mod_lbmethod_bybusyness - Apache HTTP Server</title> 9<link href="/style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" /> 10<link href="/style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" /> 11<link href="/style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" /><link rel="stylesheet" type="text/css" href="/style/css/prettify.css" /> 12<script src="/style/scripts/prettify.min.js" type="text/javascript"> 13</script> 14 15<link href="/images/favicon.ico" rel="shortcut icon" /></head> 16<body> 17<div id="page-header"> 18<p class="menu"><a href="/mod/">Modules</a> | <a href="/mod/directives.html">Directives</a> | <a href="http://wiki.apache.org/httpd/FAQ">FAQ</a> | <a href="/glossary.html">Glossary</a> | <a href="/sitemap.html">Sitemap</a></p> 19<p class="apache">Apache HTTP Server Version 2.4</p> 20<img alt="" src="/images/feather.gif" /></div> 21<div class="up"><a href="./"><img title="<-" alt="<-" src="/images/left.gif" /></a></div> 22<div id="path"> 23<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 2.4</a> > <a href="./">Modules</a></div> 24<div id="page-content"> 25<div id="preamble"><h1>Apache Module mod_lbmethod_bybusyness</h1> 26<div class="toplang"> 27<p><span>Available Languages: </span><a href="/en/mod/mod_lbmethod_bybusyness.html" title="English"> en </a> | 28<a href="/fr/mod/mod_lbmethod_bybusyness.html" hreflang="fr" rel="alternate" title="Fran�ais"> fr </a></p> 29</div> 30<table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Pending Request Counting load balancer scheduler algorithm for <code class="module"><a href="/mod/mod_proxy_balancer.html">mod_proxy_balancer</a></code></td></tr> 31<tr><th><a href="module-dict.html#Status">Status:</a></th><td>Extension</td></tr> 32<tr><th><a href="module-dict.html#ModuleIdentifier">Module�Identifier:</a></th><td>lbmethod_bybusyness_module</td></tr> 33<tr><th><a href="module-dict.html#SourceFile">Source�File:</a></th><td>mod_lbmethod_bybusyness.c</td></tr> 34<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> 35<h3>Summary</h3> 36 37<p>This module does not provide any configuration directives of its own. 38It requires the services of <code class="module"><a href="/mod/mod_proxy_balancer.html">mod_proxy_balancer</a></code>, and 39provides the <code>bybusyness</code> load balancing method.</p> 40</div> 41<div id="quickview"><h3 class="directives">Directives</h3> 42<p>This module provides no 43 directives.</p> 44<h3>Topics</h3> 45<ul id="topics"> 46<li><img alt="" src="/images/down.gif" /> <a href="#busyness">Pending Request Counting Algorithm</a></li> 47</ul><h3>See also</h3> 48<ul class="seealso"> 49<li><code class="module"><a href="/mod/mod_proxy.html">mod_proxy</a></code></li> 50<li><code class="module"><a href="/mod/mod_proxy_balancer.html">mod_proxy_balancer</a></code></li> 51</ul><ul class="seealso"><li><a href="#comments_section">Comments</a></li></ul></div> 52<div class="top"><a href="#page-header"><img alt="top" src="/images/up.gif" /></a></div> 53<div class="section"> 54<h2><a name="busyness" id="busyness">Pending Request Counting Algorithm</a></h2> 55 56 57 58 <p>Enabled via <code>lbmethod=bybusyness</code>, this scheduler keeps 59 track of how many requests each worker is currently assigned at present. A new 60 request is automatically assigned to the worker with the lowest 61 number of active requests. This is useful in the case of workers 62 that queue incoming requests independently of Apache, to ensure that 63 queue length stays even and a request is always given to the worker 64 most likely to service it the fastest and reduce latency.</p> 65 66 <p>In the case of multiple least-busy workers, the statistics (and 67 weightings) used by the Request Counting method are used to break the 68 tie. Over time, the distribution of work will come to resemble that 69 characteristic of <code>byrequests</code> (as implemented 70 by <code class="module"><a href="/mod/mod_lbmethod_byrequests.html">mod_lbmethod_byrequests</a></code>).</p> 71 72</div> 73</div> 74<div class="bottomlang"> 75<p><span>Available Languages: </span><a href="/en/mod/mod_lbmethod_bybusyness.html" title="English"> en </a> | 76<a href="/fr/mod/mod_lbmethod_bybusyness.html" hreflang="fr" rel="alternate" title="Fran�ais"> fr </a></p> 77</div><div class="top"><a href="#page-header"><img src="/images/up.gif" alt="top" /></a></div><div class="section"><h2><a id="comments_section" name="comments_section">Comments</a></h2><div class="warning"><strong>Notice:</strong><br />This is not a Q&A section. Comments placed here should be pointed towards suggestions on improving the documentation or server, and may be removed again by our moderators if they are either implemented or considered invalid/off-topic. 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