--- /dev/null
+<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
+<HTML>
+ <HEAD>
+ <TITLE>Apache module mod_mmap_static</TITLE>
+ </HEAD>
+<!-- Background white, links blue (unvisited), navy (visited), red (active) -->
+ <BODY
+ BGCOLOR="#FFFFFF"
+ TEXT="#000000"
+ LINK="#0000FF"
+ VLINK="#000080"
+ ALINK="#FF0000"
+ >
+<!--#include virtual="header.html" -->
+ <H1 ALIGN="CENTER">Module mod_mmap_static</H1>
+
+ <P>
+ This module is contained in the <CODE>mod_mmap_static.c</CODE> file, with
+ Apache 1.3 and later. It provides mmap()ing of a statically configured list
+ of frequently requested but not changed files. It is not compiled into the
+ server by default. To use <CODE>mod_mmap_static</CODE> you have to enable
+ the following line in the server build <CODE>Configuration</CODE> file:
+ <PRE>
+ AddModule modules/experimental/mod_mmap_static.o
+ </PRE>
+ </P>
+
+ <H2>Summary</H2>
+ <P>
+ This is an <STRONG>experimental</STRONG> module and should be used with
+ care. It maps a list of statically configured files (via
+ <CODE>MMapFile</CODE> directives in the main server configuration) into
+ memory through the system call <CODE>mmap()</CODE>. Although this system
+ call is not available on every platform, most of the modern Unix derivates
+ provide it. At least those ones conforming to the POSIX.4 definition. The
+ size of the mapable files usually has to be less then 2GB. But this is no
+ real restriction for documents on a webserver.
+ </P>
+ <P>
+ This mmap()ing is done once at server start or restart, only. So whenever
+ one of the mapped files changes on the filesystem you <EM>have</EM> to
+ restart the server by at least sending it a HUP or USR1 signal. To
+ reiterate that point: if the files are modified <EM>in place</EM> without
+ restarting the server you may end up serving requests that are completely
+ bogus. You should update files by unlinking the old copy and putting a new
+ copy in place. Most tools such as <CODE>rdist</CODE> and <CODE>mv</CODE> do
+ this. The reason why this modules doesn't take care of changes to the files
+ is that this check would need an extra <CODE>stat()</CODE> every time which
+ is a waste and against the intend of I/O reduction.
+ </P>
+
+ <H2>Directives</H2>
+ <UL>
+ <LI><A HREF="#mmapfile">MMapFile</A>
+ </LI>
+ </UL>
+
+ <HR>
+
+ <H2><A NAME="mmapfile">MMapFile</A></H2>
+ <P>
+ <A
+ HREF="directive-dict.html#Syntax"
+ REL="Help"
+ ><STRONG>Syntax:</STRONG></A> MMapFile <EM>filename ...</EM>
+ <BR>
+ <A
+ HREF="directive-dict.html#Default"
+ REL="Help"
+ ><STRONG>Default:</STRONG></A> <EM>None</EM>
+ <BR>
+ <A
+ HREF="directive-dict.html#Context"
+ REL="Help"
+ ><STRONG>Context:</STRONG></A> server-config
+ <BR>
+ <A
+ HREF="directive-dict.html#Override"
+ REL="Help"
+ ><STRONG>Override:</STRONG></A> <EM>Not applicable</EM>
+ <BR>
+ <A
+ HREF="directive-dict.html#Status"
+ REL="Help"
+ ><STRONG>Status:</STRONG></A> Experimental
+ <BR>
+ <A
+ HREF="directive-dict.html#Module"
+ REL="Help"
+ ><STRONG>Module:</STRONG></A> mod_mmap_static
+ <BR>
+ <A
+ HREF="directive-dict.html#Compatibility"
+ REL="Help"
+ ><STRONG>Compatibility:</STRONG></A> Only available in Apache 1.3 or later
+
+ <P>
+ The <CODE>MMapFile</CODE> directive maps one or more files (given as
+ whitespace separated arguments) into memory at server startup time. They
+ are automatically unmapped on a server shutdown. When the files have changed
+ on the filesystem at least a HUP or USR1 signal should be send to the server
+ to re-mmap them.
+ </P>
+
+ <P>
+ Be careful with the <EM>filename</EM> arguments: They have to literally
+ match the filesystem path Apache's URL-to-filename translation handlers
+ create. We cannot compare inodes or other stuff to match paths through
+ symbolic links etc. because that again would cost extra <CODE>stat()</CODE>
+ system calls which is not acceptable.
+ </P>
+
+ <P>
+ Notice: You cannot use this for speeding up CGI programs or other files
+ which are served by special content handlers. It can only be used for
+ regular files which are usually served by the Apache core content handler.
+ </P>
+
+ Example:
+
+ <PRE>
+ MMapFile /usr/local/apache/htdocs/index.html
+ </PRE>
+
+<!--#include virtual="footer.html" -->
+ </BODY>
+</HTML>
projects / apache / commitdiff