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| author |   hongbotian <hongbo.tianhongbo@huawei.com> | 2015-11-30 03:10:21 -0500 |
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| committer | hongbotian <hongbo.tianhongbo@huawei.com> | 2015-11-30 03:10:21 -0500 |
| commit | c0b7206652b2852bc574694e7ba07ba1c2acdc00 (patch) | |
| tree | 5cb95cb0e19e03610525903df46279df2c3b7eb1 /rubbos/app/httpd-2.0.64/docs/manual/misc/descriptors.html.en | |
| parent | b6d3d6e668b793220f2d3af1bc3e828553dc3fe6 (diff) | |
delete app
Change-Id: Id4c572809969ebe89e946e88063eaed262cff3f2
Signed-off-by: hongbotian <hongbo.tianhongbo@huawei.com>
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diff --git a/rubbos/app/httpd-2.0.64/docs/manual/misc/descriptors.html.en b/rubbos/app/httpd-2.0.64/docs/manual/misc/descriptors.html.en deleted file mode 100644 index 005356d6..00000000 --- a/rubbos/app/httpd-2.0.64/docs/manual/misc/descriptors.html.en +++ /dev/null @@ -1,233 +0,0 @@ -<?xml version="1.0" encoding="ISO-8859-1"?> -<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> -<html xmlns="http://www.w3.org/1999/xhtml" lang="en" xml:lang="en"><head><!-- - XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX - This file is generated from xml source: DO NOT EDIT - XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX - --> -<title>Descriptors and Apache - Apache HTTP Server</title> -<link href="../style/css/manual.css" rel="stylesheet" media="all" type="text/css" title="Main stylesheet" /> -<link href="../style/css/manual-loose-100pc.css" rel="alternate stylesheet" media="all" type="text/css" title="No Sidebar - Default font size" /> -<link href="../style/css/manual-print.css" rel="stylesheet" media="print" type="text/css" /> -<link href="../images/favicon.ico" rel="shortcut icon" /></head> -<body id="manual-page"><div id="page-header"> -<p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="../faq/">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p> -<p class="apache">Apache HTTP Server Version 2.0</p> -<img alt="" src="../images/feather.gif" /></div> -<div class="up"><a href="./"><img title="<-" alt="<-" src="../images/left.gif" /></a></div> -<div id="path"> -<a href="http://www.apache.org/">Apache</a> > <a href="http://httpd.apache.org/">HTTP Server</a> > <a href="http://httpd.apache.org/docs/">Documentation</a> > <a href="../">Version 2.0</a> > <a href="./">Miscellaneous Documentation</a></div><div id="page-content"><div id="preamble"><h1>Descriptors and Apache</h1> -<div class="toplang"> -<p><span>Available Languages: </span><a href="../en/misc/descriptors.html" title="English"> en </a></p> -</div> - - - <div class="warning"><h3>Warning:</h3> - <p>This document has not been fully updated - to take into account changes made in the 2.0 version of the - Apache HTTP Server. Some of the information may still be - relevant, but please use it with care.</p> - </div> - - <p>A <em>descriptor</em>, also commonly called a <em>file - handle</em> is an object that a program uses to read or write - an open file, or open network socket, or a variety of other - devices. It is represented by an integer, and you may be - familiar with <code>stdin</code>, <code>stdout</code>, and - <code>stderr</code> which are descriptors 0, 1, and 2 - respectively. Apache needs a descriptor for each log file, plus - one for each network socket that it listens on, plus a handful - of others. Libraries that Apache uses may also require - descriptors. Normal programs don't open up many descriptors at - all, and so there are some latent problems that you may - experience should you start running Apache with many - descriptors (<em>i.e.</em>, with many virtual hosts).</p> - - <p>The operating system enforces a limit on the number of - descriptors that a program can have open at a time. There are - typically three limits involved here. One is a kernel - limitation, depending on your operating system you will either - be able to tune the number of descriptors available to higher - numbers (this is frequently called <em>FD_SETSIZE</em>). Or you - may be stuck with a (relatively) low amount. The second limit - is called the <em>hard resource</em> limit, and it is sometimes - set by root in an obscure operating system file, but frequently - is the same as the kernel limit. The third limit is called the - <em>soft resource</em> limit. The soft limit is always less - than or equal to the hard limit. For example, the hard limit - may be 1024, but the soft limit only 64. Any user can raise - their soft limit up to the hard limit. Root can raise the hard - limit up to the system maximum limit. The soft limit is the - actual limit that is used when enforcing the maximum number of - files a process can have open.</p> - - <p>To summarize:</p> - -<div class="example"><p><code> - #open files <= soft limit <= hard limit <= kernel limit -</code></p></div> - - - <p>You control the hard and soft limits using the - <code>limit</code> (csh) or <code>ulimit</code> (sh) - directives. See the respective man pages for more information. - For example you can probably use <code>ulimit -n - unlimited</code> to raise your soft limit up to the hard limit. - You should include this command in a shell script which starts - your webserver.</p> - - <p>Unfortunately, it's not always this simple. As mentioned - above, you will probably run into some system limitations that - will need to be worked around somehow. Work was done in version - 1.2.1 to improve the situation somewhat. Here is a partial list - of systems and workarounds (assuming you are using 1.2.1 or - later).</p> - - </div> -<div id="quickview"><ul id="toc"><li><img alt="" src="../images/down.gif" /> <a href="#bsdi">BSDI 2.0</a></li> -<li><img alt="" src="../images/down.gif" /> <a href="#freebsd">FreeBSD 2.2, BSDI 2.1+</a></li> -<li><img alt="" src="../images/down.gif" /> <a href="#linux">Linux</a></li> -<li><img alt="" src="../images/down.gif" /> <a href="#solaris">Solaris through 2.5.1</a></li> -<li><img alt="" src="../images/down.gif" /> <a href="#AIX">AIX</a></li> -<li><img alt="" src="../images/down.gif" /> <a href="#sco">SCO OpenServer</a></li> -<li><img alt="" src="../images/down.gif" /> <a href="#tru64">Compaq Tru64 UNIX/Digital UNIX/OSF</a></li> -<li><img alt="" src="../images/down.gif" /> <a href="#others">Others</a></li> -</ul></div> -<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> -<div class="section"> -<h2><a name="bsdi" id="bsdi">BSDI 2.0</a></h2> - - <p>Under BSDI 2.0 you can build Apache to support more - descriptors by adding <code>-DFD_SETSIZE=nnn</code> to - <code>EXTRA_CFLAGS</code> (where nnn is the number of - descriptors you wish to support, keep it less than the hard - limit). But it will run into trouble if more than - approximately 240 Listen directives are used. This may be - cured by rebuilding your kernel with a higher - FD_SETSIZE.</p> - - </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> -<div class="section"> -<h2><a name="freebsd" id="freebsd">FreeBSD 2.2, BSDI 2.1+</a></h2> - - <p>Similar to the BSDI 2.0 case, you should define - <code>FD_SETSIZE</code> and rebuild. But the extra Listen - limitation doesn't exist.</p> - - </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> -<div class="section"> -<h2><a name="linux" id="linux">Linux</a></h2> - - <p>By default Linux has a kernel maximum of 256 open - descriptors per process. There are several patches available - for the 2.0.x series which raise this to 1024 and beyond, and - you can find them in the "unofficial patches" section of <a href="http://www.linuxhq.com/">the Linux Information HQ</a>. - None of these patches are perfect, and an entirely different - approach is likely to be taken during the 2.1.x development. - Applying these patches will raise the FD_SETSIZE used to - compile all programs, and unless you rebuild all your - libraries you should avoid running any other program with a - soft descriptor limit above 256. As of this writing the - patches available for increasing the number of descriptors do - not take this into account. On a dedicated webserver you - probably won't run into trouble.</p> - - </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> -<div class="section"> -<h2><a name="solaris" id="solaris">Solaris through 2.5.1</a></h2> - - <p>Solaris has a kernel hard limit of 1024 (may be lower in - earlier versions). But it has a limitation that files using - the stdio library cannot have a descriptor above 255. Apache - uses the stdio library for the ErrorLog directive. When you - have more than approximately 110 virtual hosts (with an error - log and an access log each) you will need to build Apache - with <code>-DHIGH_SLACK_LINE=256</code> added to - <code>EXTRA_CFLAGS</code>. You will be limited to - approximately 240 error logs if you do this.</p> - - </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> -<div class="section"> -<h2><a name="AIX" id="AIX">AIX</a></h2> - - <p>AIX version 3.2?? appears to have a hard limit of 128 - descriptors. End of story. Version 4.1.5 has a hard limit of - 2000.</p> - - </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> -<div class="section"> -<h2><a name="sco" id="sco">SCO OpenServer</a></h2> - - <p>Edit the <code>/etc/conf/cf.d/stune</code> file or use - <code>/etc/conf/cf.d/configure</code> choice 7 (User and - Group configuration) and modify the <code>NOFILES</code> - kernel parameter to a suitably higher value. SCO recommends a - number between 60 and 11000, the default is 110. Relink and - reboot, and the new number of descriptors will be - available.</p> - - </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> -<div class="section"> -<h2><a name="tru64" id="tru64">Compaq Tru64 UNIX/Digital UNIX/OSF</a></h2> - - <ol> - <li>Raise <code>open_max_soft</code> and - <code>open_max_hard</code> to 4096 in the proc subsystem. - Do a man on sysconfig, sysconfigdb, and - sysconfigtab.</li> - - <li>Raise <code>max-vnodes</code> to a large number which - is greater than the number of apache processes * 4096 - (Setting it to 250,000 should be good for most people). - Do a man on sysconfig, sysconfigdb, and - sysconfigtab.</li> - - <li>If you are using Tru64 5.0, 5.0A, or 5.1, define - <code>NO_SLACK</code> to work around a bug in the OS. - <code>CFLAGS="-DNO_SLACK" ./configure</code></li> - </ol> - - </div><div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif" /></a></div> -<div class="section"> -<h2><a name="others" id="others">Others</a></h2> - - <p>If you have details on another operating system, please - submit it through our <a href="http://httpd.apache.org/bug_report.html">Bug Report - Page</a>.</p> - - <p>In addition to the problems described above there are - problems with many libraries that Apache uses. The most common - example is the bind DNS resolver library that is used by pretty - much every unix, which fails if it ends up with a descriptor - above 256. We suspect there are other libraries that similar - limitations. So the code as of 1.2.1 takes a defensive stance - and tries to save descriptors less than 16 for use while - processing each request. This is called the <em>low slack - line</em>.</p> - - <p>Note that this shouldn't waste descriptors. If you really - are pushing the limits and Apache can't get a descriptor above - 16 when it wants it, it will settle for one below 16.</p> - - <p>In extreme situations you may want to lower the low slack - line, but you shouldn't ever need to. For example, lowering it - can increase the limits 240 described above under Solaris and - BSDI 2.0. But you'll play a delicate balancing game with the - descriptors needed to serve a request. Should you want to play - this game, the compile time parameter is - <code>LOW_SLACK_LINE</code> and there's a tiny bit of - documentation in the header file <code>httpd.h</code>.</p> - - <p>Finally, if you suspect that all this slack stuff is causing - you problems, you can disable it. Add <code>-DNO_SLACK</code> - to <code>EXTRA_CFLAGS</code> and rebuild. But please report it - to our <a href="http://httpd.apache.org/bug_report.html">Bug - Report Page</a> so that we can investigate. </p> - - </div></div> -<div class="bottomlang"> -<p><span>Available Languages: </span><a href="../en/misc/descriptors.html" title="English"> en </a></p> -</div><div id="footer"> -<p class="apache">Copyright 2009 The Apache Software Foundation.<br />Licensed under the <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache License, Version 2.0</a>.</p> -<p class="menu"><a href="../mod/">Modules</a> | <a href="../mod/directives.html">Directives</a> | <a href="../faq/">FAQ</a> | <a href="../glossary.html">Glossary</a> | <a href="../sitemap.html">Sitemap</a></p></div> -</body></html>
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