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Posted to cvs@httpd.apache.org by rb...@apache.org on 2003/03/10 05:35:09 UTC
cvs commit: httpd-2.0/docs/manual/misc perf-tuning.xml
rbowen 2003/03/09 20:35:08
Modified: docs/manual/misc Tag: APACHE_2_0_BRANCH perf-tuning.xml
Log:
Added a little bit of text, and added section titles, so that these
sections can be linked to directly. Unfortunately, I cannot get this to
build, and I've spent entirely too long staring at it. Can someone
figure out what is invalid with my xml here? Thanks.
Revision Changes Path
No revision
No revision
1.3.2.3 +66 -24 httpd-2.0/docs/manual/misc/perf-tuning.xml
Index: perf-tuning.xml
===================================================================
RCS file: /home/cvs/httpd-2.0/docs/manual/misc/perf-tuning.xml,v
retrieving revision 1.3.2.2
retrieving revision 1.3.2.3
diff -u -r1.3.2.2 -r1.3.2.3
--- perf-tuning.xml 5 Jan 2003 04:01:19 -0000 1.3.2.2
+++ perf-tuning.xml 10 Mar 2003 04:35:08 -0000 1.3.2.3
@@ -44,12 +44,16 @@
<p>The single biggest hardware issue affecting webserver
performance is RAM. A webserver should never ever have to swap,
- swapping increases the latency of each request beyond a point
+ as swapping increases the latency of each request beyond a point
that users consider "fast enough". This causes users to hit
stop and reload, further increasing the load. You can, and
should, control the <directive module="mpm_common"
>MaxClients</directive> setting so that your server
- does not spawn so many children it starts swapping.</p>
+ does not spawn so many children it starts swapping. This procedure
+ for doing this is simple: determine the size of your average Apache
+ process, by looking at your process list via a tool such as
+ <code>top</code>, and divide this into your total available memory,
+ leaving some room for other processes.</p>
<p>Beyond that the rest is mundane: get a fast enough CPU, a
fast enough network card, and fast enough disks, where "fast
@@ -105,21 +109,34 @@
</directivelist>
</related>
- <section>
+ <section id="dns">
- <title>HostnameLookups</title>
+ <title>HostnameLookups and other DNS considerations</title>
<p>Prior to Apache 1.3, <directive module="core"
>HostnameLookups</directive> defaulted to <code>On</code>.
This adds latency to every request because it requires a
DNS lookup to complete before the request is finished. In
- Apache 1.3 this setting defaults to <code>Off</code>.
- However (1.3 or later), if you use any <code>Allow from domain</code>
- or <code>Deny from domain</code> directives then you will pay for
+ Apache 1.3 this setting defaults to <code>Off</code>. If you need
+ to have addresses in your log files resolved to hostnames, use the
+ <a href="../programs/logresolve.html"><code>logresolve</code></a>
+ program that comes with Apache, on one of the numerous log
+ reporting packages which are available.</p>
+
+ <p>It is recommended that you do this sort of postprocessing of
+ your log files on some machine other than the production web
+ server machine, in order that this activity not adversely affect
+ server performance.</p>
+
+ If you use any <code><directive module="access">Allow</directive>
+ from domain</code> or <code><directive
+ module="access">Deny</directive> from domain</code>
+ directives (i.e., using a hostname, or a domain name, rather than
+ an IP address) then you will pay for
a double reverse DNS lookup (a reverse, followed by a forward
- to make sure that the reverse is not being spoofed). So for the
- highest performance avoid using these directives (it's fine to
- use IP addresses rather than domain names).</p>
+ to make sure that the reverse is not being spoofed). For best
+ performence, therefore, use IP addresses, rather than names, when
+ using these directives, if possible.</p>
<p>Note that it's possible to scope the directives, such as
within a <code><Location /server-status></code> section.
@@ -140,19 +157,9 @@
could consider doing the <code>gethostbyname</code> call in the
specific CGIs that need it.</p>
- <p>Similarly, if you need to have hostname information in your
- server logs in order to generate reports of this information,
- you can postprocess your log file with <a
- href="../programs/logresolve.html"><code>logresolve</code></a>,
- so that these lookups can be done without making the client wait.
- It is recommended that you do this postprocessing, and any other
- statistical analysis of the log file, somewhere other than your
- production web server machine, in order that this activity does
- not adversely affect server performance.</p>
-
</section>
- <section>
+ <section id="symlinks">
<title>FollowSymLinks and SymLinksIfOwnerMatch</title>
@@ -205,7 +212,7 @@
</section>
- <section>
+ <section id="htacess">
<title>AllowOverride</title>
@@ -233,7 +240,7 @@
</section>
- <section>
+ <section id="negotiation">
<title>Negotiation</title>
@@ -261,6 +268,13 @@
determined by reading this single file, rather than having to
scan the directory for files.</p>
+ <p>If your site needs content negotiation consider using
+ <code>type-map</code> files, rather than the <code>Options
+ MultiViews</code> directive to accomplish the negotiation. See the
+ <a href="../content-negotiation.html">Content Negotiation</a>
+ documentation for a full discussion of the methods of negotiation,
+ and instructions for creating <code>type-map</code> files.</p>
+
</section>
<section>
@@ -331,7 +345,7 @@
</section>
- <section>
+ <section id="process">
<title>Process Creation</title>
@@ -437,6 +451,34 @@
<p>For more information on these and other MPMs, please
see the MPM <a href="../mpm.html">documentation</a>.</p>
+
+ </section>
+
+ <section id="modules">
+
+ <title>Modules</title>
+
+ <p>Since memory usage is such an important consideration in
+ performance, you should attempt to eliminate modules that youare
+ not actually using. If you have built the modules as <a
+ href="../dso.html">DSOs</a>, eliminating modules is a simple
+ matter of commenting out the associated <directive
+ module="so">LoadModule</directive> directive for that module.
+ This allows you to experiment with removing modules, and seeing
+ if your site still functions in their absense.</p>
+
+ <p>If, on the other hand, you have modules statically linked
+ into your Apache binary, you will need to recompile Apache in
+ order to remove unwanted modules.</p>
+
+ <p>An associated question that arises here is, of course, what
+ modules you need, and which ones you don't. The answer here
+ will, of course, vary from one web site to another. However, the
+ <i>minimal</i> list of modules which you can get by with tends
+ to include <module>mod_mime</module>, <module>mod_dir</module>,
+ and <module>mod_log_config</module>. <code>mod_log_config</code> is,
+ of course, optional, as you can run a web site without log
+ files. This is, however, not recommended.</p>
</section>