File: //proc/thread-self/root/usr/share/doc/varnish-6.0.3/html/users-guide/sizing-your-cache.html
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="X-UA-Compatible" content="IE=Edge" />
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Sizing your cache — Varnish version 6.0.3 documentation</title>
<link rel="stylesheet" href="../_static/classic.css" type="text/css" />
<link rel="stylesheet" href="../_static/pygments.css" type="text/css" />
<script type="text/javascript" id="documentation_options" data-url_root="../" src="../_static/documentation_options.js"></script>
<script type="text/javascript" src="../_static/jquery.js"></script>
<script type="text/javascript" src="../_static/underscore.js"></script>
<script type="text/javascript" src="../_static/doctools.js"></script>
<link rel="index" title="Index" href="../genindex.html" />
<link rel="search" title="Search" href="../search.html" />
<link rel="next" title="VCL - Varnish Configuration Language" href="vcl.html" />
<link rel="prev" title="Parameters" href="params.html" />
</head><body>
<div class="related" role="navigation" aria-label="related navigation">
<h3>Navigation</h3>
<ul>
<li class="right" style="margin-right: 10px">
<a href="../genindex.html" title="General Index"
accesskey="I">index</a></li>
<li class="right" >
<a href="vcl.html" title="VCL - Varnish Configuration Language"
accesskey="N">next</a> |</li>
<li class="right" >
<a href="params.html" title="Parameters"
accesskey="P">previous</a> |</li>
<li class="nav-item nav-item-0"><a href="../index.html">Varnish version 6.0.3 documentation</a> »</li>
<li class="nav-item nav-item-1"><a href="index.html" >The Varnish Users Guide</a> »</li>
<li class="nav-item nav-item-2"><a href="running.html" accesskey="U">Starting and running Varnish</a> »</li>
</ul>
</div>
<div class="document">
<div class="documentwrapper">
<div class="bodywrapper">
<div class="body" role="main">
<div class="section" id="sizing-your-cache">
<h1>Sizing your cache<a class="headerlink" href="#sizing-your-cache" title="Permalink to this headline">ΒΆ</a></h1>
<p>Deciding on cache size can be a tricky task. A few things to consider:</p>
<blockquote>
<div><ul class="simple">
<li>How big is your <em>hot</em> data set. For a portal or news site that
would be the size of the front page with all the stuff on it, and
the size of all the pages and objects linked from the first page.</li>
<li>How expensive is it to generate an object? Sometimes it makes sense
to only cache images a little while or not to cache them at all if
they are cheap to serve from the backend and you have a limited
amount of memory.</li>
<li>Watch the <cite>n_lru_nuked</cite> counter with <a class="reference internal" href="../reference/varnishstat.html#varnishstat-1"><span class="std std-ref">varnishstat</span></a> or some
other tool. If you have a lot of LRU activity then your cache is
evicting objects due to space constraints and you should consider
increasing the size of the cache.</li>
</ul>
</div></blockquote>
<p>Be aware that every object that is stored also carries overhead that
is kept outside the actually storage area. So, even if you specify <code class="docutils literal notranslate"><span class="pre">-s</span>
<span class="pre">malloc,16G</span></code> Varnish might actually use <strong>double</strong> that. Varnish has a
overhead of about 1KB per object. So, if you have lots of small objects
in your cache the overhead might be significant.</p>
</div>
</div>
</div>
</div>
<div class="sphinxsidebar" role="navigation" aria-label="main navigation">
<div class="sphinxsidebarwrapper">
<h4>Previous topic</h4>
<p class="topless"><a href="params.html"
title="previous chapter">Parameters</a></p>
<h4>Next topic</h4>
<p class="topless"><a href="vcl.html"
title="next chapter">VCL - Varnish Configuration Language</a></p>
<div role="note" aria-label="source link">
<h3>This Page</h3>
<ul class="this-page-menu">
<li><a href="../_sources/users-guide/sizing-your-cache.rst.txt"
rel="nofollow">Show Source</a></li>
</ul>
</div>
<div id="searchbox" style="display: none" role="search">
<h3>Quick search</h3>
<div class="searchformwrapper">
<form class="search" action="../search.html" method="get">
<input type="text" name="q" />
<input type="submit" value="Go" />
<input type="hidden" name="check_keywords" value="yes" />
<input type="hidden" name="area" value="default" />
</form>
</div>
</div>
<script type="text/javascript">$('#searchbox').show(0);</script>
</div>
</div>
<div class="clearer"></div>
</div>
<div class="related" role="navigation" aria-label="related navigation">
<h3>Navigation</h3>
<ul>
<li class="right" style="margin-right: 10px">
<a href="../genindex.html" title="General Index"
>index</a></li>
<li class="right" >
<a href="vcl.html" title="VCL - Varnish Configuration Language"
>next</a> |</li>
<li class="right" >
<a href="params.html" title="Parameters"
>previous</a> |</li>
<li class="nav-item nav-item-0"><a href="../index.html">Varnish version 6.0.3 documentation</a> »</li>
<li class="nav-item nav-item-1"><a href="index.html" >The Varnish Users Guide</a> »</li>
<li class="nav-item nav-item-2"><a href="running.html" >Starting and running Varnish</a> »</li>
</ul>
</div>
<div class="footer" role="contentinfo">
© Copyright 2010-2014, Varnish Software AS.
Created using <a href="http://sphinx-doc.org/">Sphinx</a> 1.7.6.
</div>
</body>
</html>