1<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 2 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 3 4<html xmlns="http://www.w3.org/1999/xhtml"> 5 <head> 6 <meta name="generator" content="HTML Tidy, see www.w3.org" /> 7 8 <title>Hints on Running a High-Performance Web Server</title> 9 </head> 10 <!-- Background white, links blue (unvisited), navy (visited), red (active) --> 11 12 <body bgcolor="#FFFFFF" text="#000000" link="#0000FF" 13 vlink="#000080" alink="#FF0000"> 14 <div align="CENTER"> 15 <img src="../images/sub.gif" alt="[APACHE DOCUMENTATION]" /> 16 17 <h3>Apache HTTP Server Version 1.3</h3> 18 </div> 19 20 21 <h1 align="CENTER">Hints on Running a High-Performance Web 22 Server</h1> 23 Running Apache on a heavily loaded web server, one often 24 encounters problems related to the machine and OS 25 configuration. "Heavy" is relative, of course - but if you are 26 seeing more than a couple hits per second on a sustained basis 27 you should consult the pointers on this page. In general the 28 suggestions involve how to tune your kernel for the heavier TCP 29 load, hardware/software conflicts that arise, <em>etc.</em> 30 31 <ul> 32 <li><a href="#AUX">A/UX (Apple's UNIX)</a></li> 33 34 <li><a href="#BSD">BSD-based (BSDI, FreeBSD, etc)</a></li> 35 36 <li><a href="#DEC">Digital UNIX</a></li> 37 38 <li><a href="perf-hp.html">HPUX</a></li> 39 40 <li><a href="#irix">IRIX</a></li> 41 42 <li><a href="#Linux">Linux</a></li> 43 44 <li><a href="#Solaris">Solaris</a></li> 45 46 <li><a href="#SunOS">SunOS 4.x</a></li> 47 48 <li><a href="#SVR4">SVR4</a></li> 49 </ul> 50 <hr /> 51 52 <h3><a id="AUX" name="AUX">A/UX (Apple's UNIX)</a></h3> 53 If you are running Apache on A/UX, a page that gives some 54 helpful performance hints (concerning the <em>listen()</em> 55 queue and using virtual hosts) <a 56 href="http://www.jaguNET.com/apache.html">can be found here</a> 57 58 <hr /> 59 60 <h3><a id="BSD" name="BSD">BSD-based (BSDI, FreeBSD, 61 etc)</a></h3> 62 <a href="perf-bsd44.html#initial">Quick</a> and <a 63 href="perf-bsd44.html#detail">detailed</a> performance tuning 64 hints for BSD-derived systems. <a 65 href="perf-bsd44.html#accf">Accept filtering</a> on FreeBSD. 66 <hr /> 67 68 <h3><a id="DEC" name="DEC">Digital UNIX</a></h3> 69 70 <ul> 71 <li><a 72 href="http://www.sean.de/Solaris/tune.html"> 73 Solaris 2.x - tuning your TCP/IP stack</a> contains some good 74 technical information about tuning various Solaris TCP/IP 75 parameters.</li> 76 </ul> 77 <hr /> 78 79 <h3><a id="SunOS" name="SunOS">SunOS 4.x</a></h3> 80 More information on tuning SOMAXCONN on SunOS can be found at 81 <a 82 href="http://www.islandnet.com/~mark/somaxconn.html">http://www.islandnet.com/~mark/somaxconn.html</a>. 83 84 <hr /> 85 86 <h3><a id="SVR4" name="SVR4">SVR4</a></h3> 87 Some SVR4 versions waste three system calls on every 88 <samp>gettimeofday()</samp> call. Depending on the syntactic 89 form of the <samp>TZ</samp> environment variable, these systems 90 have several different algorithms to determine the local time 91 zone (presumably <em>compatible</em> with something). The 92 following example uses the central european time zone to 93 demonstrate this: 94 95 <dl> 96 <dt><strong>TZ=:MET</strong></dt> 97 98 <dd> 99 This form delegates the knowledge of the time zone 100 information to an external compiled zoneinfo file (à 101 la BSD).<br /> 102 <strong>Caveat:</strong> Each time the gettimeofday() 103 function is called, the external zone info is read in again 104 (at least on some SVR4 systems). That results in three 105 wasted system calls with every apache request served. 106<pre> 107 open("/usr/lib/locale/TZ/MET", O_RDONLY) = 3 108 read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 7944) = 778 109 close(3) = 0 110</pre> 111 </dd> 112 113 <dt> 114 <strong>TZ=MET-1MDT,M3.5.0/02:00:00,M10.5.0/03:00:00</strong></dt> 115 116 <dd>This syntax form (à la SYSV) contains all the 117 knowledge about time zone beginning and ending times in its 118 external representation. It has to be parsed each time it is 119 evaluated, resulting in a slight computing overhead, but it 120 requires no system call. Though the table lookup à la 121 BSD is the more sophisticated technical solution, the bad 122 SVR4 implementation makes this the preferred syntax on 123 systems which otherwise access the external zone info file 124 repeatedly.</dd> 125 </dl> 126 You should use the <samp>truss</samp> utility on a 127 single-process apache server (started with the <samp>-X</samp> 128 debugging switch) to determine whether your system can profit 129 from the second form of the <samp>TZ</samp> environment 130 variable. If it does, you could integrate the setting of the 131 preferred <samp>TZ</samp> syntax into the httpd startup script, 132 which is usually simply a copy of (or symbolic link to) the 133 <samp>apachectl</samp> utility script, or into the system's 134 <samp>/etc/TIMEZONE</samp> script. 135 <hr /> 136 137 <h3>More welcome!</h3> 138 If you have tips to contribute, please submit them to 139 the <a href="http://bugs.apache.org/">Apache Bug 140 Database</a>. 141 142 <hr /> 143 144 <h3 align="CENTER">Apache HTTP Server Version 1.3</h3> 145 <a href="./"><img src="../images/index.gif" alt="Index" /></a> 146 <a href="../"><img src="../images/home.gif" alt="Home" /></a> 147 148 </body> 149</html> 150 151
