detsports.ru





mod_file_cache - Apache HTTP Server Version 2.4









Modules | Directives | FAQ | Glossary | Sitemap
Apache HTTP Server Version 2.4



Apache > HTTP Server > Documentation > Version 2.4 > Modules

Apache Module mod_file_cache

Available Languages:  en  |
 fr  |
 ko 

Description:Caches a static list of files in memory
Status:Experimental
ModuleIdentifier:file_cache_module
SourceFile:mod_file_cache.c
Summary


    
      This module should be used with care. You can easily create a broken
      site using mod_file_cache, so read this document
      carefully.
    

    Caching frequently requested files that change very
    infrequently is a technique for reducing server load.
    mod_file_cache provides two techniques for caching
    frequently requested static files. Through configuration
    directives, you can direct mod_file_cache to either
    open then mmap() a file, or to pre-open a file and save
    the file's open file handle. Both techniques reduce server
    load when processing requests for these files by doing part of the work
    (specifically, the file I/O) for serving the file when the
    server is started rather than during each request.

    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.

    This module is an extension of and borrows heavily from the
    mod_mmap_static module in Apache 1.3.

Topics

 Using mod_file_cache
Directives

 CacheFile
 MMapFile

Bugfix checklisthttpd changelogKnown issuesReport a bugSee also

Comments


Using mod_file_cache

    mod_file_cache caches a list of statically
    configured files via MMapFile or CacheFile directives in the main server configuration.

    Not all platforms support both directives. You will receive an error
    message in the server error log if you attempt to use an
    unsupported directive. If given an unsupported directive, the
    server will start but the file will not be cached. On platforms
    that support both directives, you should experiment with both to
    see which works best for you.

    MMapFile Directive

      The MMapFile
      directive of mod_file_cache maps a list of
      statically configured files into memory through the system call
      mmap(). This system call is available on most modern
      Unix derivatives, but not on all. There are sometimes system-specific
      limits on the size and number of files that can be
      mmap()ed, experimentation is probably the easiest way
      to find out.

      This mmap()ing is done once at server start or
      restart, only. So whenever one of the mapped files changes on the
      filesystem you have to restart the server (see the Stopping and Restarting documentation).
      To reiterate that point: if the files are modified in place
      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
      rdist and mv do this. The reason why this
      modules doesn't take care of changes to the files is that this check
      would need an extra stat() every time which is a waste
      and against the intent of I/O reduction.
    

    CacheFile Directive

      The CacheFile
      directive of mod_file_cache opens an active
      handle or file descriptor to the file (or files)
      listed in the configuration directive and places these open file
      handles in the cache. When the file is requested, the server
      retrieves the handle from the cache and passes it to the
      sendfile() (or TransmitFile() on Windows),
      socket API.

      

      This file handle caching is done once at server start or
      restart, only. So whenever one of the cached files changes on
      the filesystem you have to restart the server (see the
      Stopping and Restarting
      documentation). To reiterate that point: if the files are
      modified in place 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 rdist and
      mv do this.
    

    Note
      Don't bother asking for a directive which recursively
      caches all the files in a directory. Try this instead... See the
      Include directive, and consider
      this command:

      
        find /www/htdocs -type f -print \
        | sed -e 's/.*/mmapfile &/' > /www/conf/mmap.conf
      
    


CacheFile Directive

Description:Cache a list of file handles at startup time
Syntax:CacheFile file-path [file-path] ...
Context:server config
Status:Experimental
Module:mod_file_cache

    The CacheFile directive opens handles to
    one or more files (given as whitespace separated arguments) and
    places these handles into the cache at server startup
    time. Handles to cached files are automatically closed on a server
    shutdown.  When the files have changed on the filesystem, the
    server should be restarted to re-cache them.

    Be careful with the file-path 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 stat() system
    calls which is not acceptable. This module may or may not work
    with filenames rewritten by mod_alias or
    mod_rewrite.

    ExampleCacheFile /usr/local/apache/htdocs/index.html




MMapFile Directive

Description:Map a list of files into memory at startup time
Syntax:MMapFile file-path [file-path] ...
Context:server config
Status:Experimental
Module:mod_file_cache

    The MMapFile 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.

    Be careful with the file-path 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 stat() system
    calls which is not acceptable. This module may or may not work
    with filenames rewritten by mod_alias or
    mod_rewrite.

    ExampleMMapFile /usr/local/apache/htdocs/index.html





Available Languages:  en  |
 fr  |
 ko 
CommentsNotice: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. Questions on how to manage the Apache HTTP Server should be directed at either our IRC channel, #httpd, on Freenode, or sent to our mailing lists.

Copyright 2017 The Apache Software Foundation.Licensed under the Apache License, Version 2.0.
Modules | Directives | FAQ | Glossary | Sitemap
page_1 | page_2 | page_3 | page_4 | page_5 | сальса.рф
Warning: simplexml_load_file(): sites/detsports.ru.xml:567: parser error : Extra content at the end of the document in /home/artem/pool/index.php on line 77

Warning: simplexml_load_file(): t> in /home/artem/pool/index.php on line 77

Warning: simplexml_load_file(): ^ in /home/artem/pool/index.php on line 77

Fatal error: Call to a member function xpath() on a non-object in /home/artem/pool/index.php on line 82