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<title>Chapter�2.�BIND Resource Requirements</title>
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<tr><th colspan="3" align="center">Chapter�2.�<acronym class="acronym">BIND</acronym> Resource Requirements</th></tr>
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<div class="titlepage"><div><div><h1 class="title">
<a name="Bv9ARM.ch02"></a>Chapter�2.�<acronym class="acronym">BIND</acronym> Resource Requirements</h1></div></div></div>
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<p><b>Table of Contents</b></p>
<dl class="toc">
<dt><span class="section"><a href="Bv9ARM.ch02.html#intensive_env">Name Server Intensive Environment Issues</a></span></dt>
<dt><span class="section"><a href="Bv9ARM.ch02.html#supported_os">Supported Operating Systems</a></span></dt>
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<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="hw_req"></a>Hardware requirements</h2></div></div></div>
<p>
<acronym class="acronym">DNS</acronym> hardware requirements have
traditionally been quite modest.
For many installations, servers that have been pensioned off from
active duty have performed admirably as <acronym class="acronym">DNS</acronym> servers.
</p>
<p>
The DNSSEC features of <acronym class="acronym">BIND</acronym> 9
may prove to be quite
CPU intensive however, so organizations that make heavy use of these
features may wish to consider larger systems for these applications.
<acronym class="acronym">BIND</acronym> 9 is fully multithreaded, allowing
full utilization of
multiprocessor systems for installations that need it.
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<div class="section">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="cpu_req"></a>CPU Requirements</h2></div></div></div>
<p>
CPU requirements for <acronym class="acronym">BIND</acronym> 9 range from
i486-class machines
for serving of static zones without caching, to enterprise-class
machines if you intend to process many dynamic updates and DNSSEC
signed zones, serving many thousands of queries per second.
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<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="mem_req"></a>Memory Requirements</h2></div></div></div>
<p>
The memory of the server has to be large enough to fit the
cache and zones loaded off disk. The <span class="command"><strong>max-cache-size</strong></span>
option can be used to limit the amount of memory used by the cache,
at the expense of reducing cache hit rates and causing more <acronym class="acronym">DNS</acronym>
traffic.
Additionally, if additional section caching
(<a class="xref" href="Bv9ARM.ch06.html#acache" title="Additional Section Caching">the section called “Additional Section Caching”</a>) is enabled,
the <span class="command"><strong>max-acache-size</strong></span> option can be used to
limit the amount
of memory used by the mechanism.
It is still good practice to have enough memory to load
all zone and cache data into memory — unfortunately, the best
way
to determine this for a given installation is to watch the name server
in operation. After a few weeks the server process should reach
a relatively stable size where entries are expiring from the cache as
fast as they are being inserted.
</p>
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<div class="section">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="intensive_env"></a>Name Server Intensive Environment Issues</h2></div></div></div>
<p>
For name server intensive environments, there are two alternative
configurations that may be used. The first is where clients and
any second-level internal name servers query a main name server, which
has enough memory to build a large cache. This approach minimizes
the bandwidth used by external name lookups. The second alternative
is to set up second-level internal name servers to make queries
independently.
In this configuration, none of the individual machines needs to
have as much memory or CPU power as in the first alternative, but
this has the disadvantage of making many more external queries,
as none of the name servers share their cached data.
</p>
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<div class="section">
<div class="titlepage"><div><div><h2 class="title" style="clear: both">
<a name="supported_os"></a>Supported Operating Systems</h2></div></div></div>
<p>
ISC <acronym class="acronym">BIND</acronym> 9 compiles and runs on a large
number
of Unix-like operating systems and on
Microsoft Windows Server 2003 and 2008, and Windows XP and Vista.
For an up-to-date
list of supported systems, see the README file in the top level
directory
of the BIND 9 source distribution.
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<td width="40%" align="left" valign="top">Chapter�1.�Introduction�</td>
<td width="40%" align="right" valign="top">�Chapter�3.�Name Server Configuration</td>
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<p xmlns:db="http://docbook.org/ns/docbook" style="text-align: center;">BIND 9.11.3 (Extended Support Version)</p>
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