<!DOCTYPE html>
<head>
<meta charset="utf-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1" />
<title>LiteSpeed Web Server Users' Manual - Server Log</title>
<meta name="description" content="LiteSpeed Web Server Users' Manual - Server Log." />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<meta name="robots" content="noindex">
<link rel="shortcut icon" href="img/favicon.ico" />
<link rel="stylesheet" type="text/css" href="css/hdoc.css">
</head>
<body>
<div class="pagewrapper clearfix"><aside class="sidetree ls-col-1-5">
<figure>
<img src="img/lsws_logo.svg" alt="lightspeed web server logo"
width="100px"/>
</figure>
<h2 class="ls-text-thin">
LiteSpeed Web Server
<br />
<span class="current"><a href="index.html">Users' Manual</a></span>
</h2>
<h3 class="ls-text-muted">Version 6.3 — Rev. 2</h3>
<hr/>
<div>
<ul>
<li><a href="license.html">License Enterprise</a></li>
<li><a href="intro.html">Introduction</a></li>
<li><a href="install.html">Installation</a></li>
<li>
<a href="admin.html">Administration</a>
<ul class="menu level2">
<li><a href="ServerStat_Help.html">Service Manager</a></li>
<li><a href="Real_Time_Stats_Help.html">Real-Time Stats</a></li>
</ul>
</li>
<li><a href="security.html">Security</a></li>
<li>
<a href="config.html">Configuration</a>
<ul class="level2">
<li><a href="ServGeneral_Help.html">Server General</a></li>
<li><span class="current"><a href="ServLog_Help.html">Server Log</a></span></li>
<li><a href="ServTuning_Help.html">Server Tuning</a></li>
<li><a href="ServSecurity_Help.html">Server Security</a></li>
<li><a href="Cache_Help.html">Page Cache</a></li>
<li><a href="PageSpeed_Config.html">PageSpeed Config</a></li>
<li><a href="ExtApp_Help.html">External Apps</a></li>
<ul class="level3">
<li><a href="External_FCGI.html">Fast CGI App</a></li>
<li><a href="External_FCGI_Auth.html">Fast CGI Authorizer</a></li>
<li><a href="External_LSAPI.html">LSAPI App</a></li>
<li><a href="External_Servlet.html">Servlet Engine</a></li>
<li><a href="External_WS.html">Web Server</a></li>
<li><a href="External_PL.html">Piped logger</a></li>
<li><a href="External_LB.html">Load Balancer</a></li>
</ul>
<li><a href="ScriptHandler_Help.html">Script Handler</a></li>
<li><a href="PHP_Help.html">PHP</a></li>
<li><a href="App_Server_Help.html">App Server Settings</a></li>
<li><a href="Listeners_General_Help.html">Listener General</a></li>
<li><a href="Listeners_SSL_Help.html">Listener SSL</a></li>
<li><a href="Templates_Help.html">Virtual Host Templates</a></li>
<li><a href="VirtualHosts_Help.html">Virtual Host Basic</a></li>
<li><a href="VHGeneral_Help.html">Virtual Host General</a></li>
<li><a href="VHSecurity_Help.html">Virtual Host Security</a></li>
<li><a href="VHSSL_Help.html">Virtual Host SSL</a></li>
<li>
<a href="VHPageSpeed_Config.html">Virtual Host PageSpeed Config</a>
</li>
<li><a href="Rewrite_Help.html">Rewrite</a></li>
<li><a href="Context_Help.html">Context</a></li>
<ul class="level3">
<li><a href="Static_Context.html">Static Context</a></li>
<li>
<a href="Java_Web_App_Context.html">Java Web App Context</a>
</li>
<li><a href="Servlet_Context.html">Servlet Context</a></li>
<li><a href="FCGI_Context.html">Fast CGI Context</a></li>
<li><a href="LSAPI_Context.html">LSAPI Context</a></li>
<li><a href="Proxy_Context.html">Proxy Context</a></li>
<li><a href="CGI_Context.html">CGI Context</a></li>
<li><a href="LB_Context.html">Load Balancer Context</a></li>
<li><a href="Redirect_Context.html">Redirect Context</a></li>
<li><a href="App_Server_Context.html">App Server Context</a></li>
<li><a href="Rails_Context.html">Rack/Rails Context</a></li>
</ul>
<li><a href="VHAddOns_Help.html">Add-ons</a></li>
</ul>
</li>
<li>
<a href="webconsole.html">Web Console</a>
<ul class="level2">
<li><a href="AdminGeneral_Help.html">Admin Console General</a></li>
<li><a href="AdminSecurity_Help.html">Admin Console Security</a></li>
<li>
<a href="AdminListeners_General_Help.html">
Admin Listener General
</a>
</li>
<li>
<a href="AdminListeners_SSL_Help.html">Admin Listener SSL</a>
</li>
</ul>
</li>
</ul>
</div>
</aside>
<article class="contentwrapper ls-col-3-5 clearfix"><div class="nav-bar ls-spacer-micro-top"><div class="prev">« <a href="ServGeneral_Help.html">Server General</a></div><div class="center"><a href="config.html">Configuration</a></div><div class="next"><a href="ServTuning_Help.html">Server Tuning</a> »</div></div>
<h1>Server Log</h1><h2 id="top">Table of Contents</h2><section class="toc"><section class="toc-row"><header>Server Log</header><p>
<a href="#log_fileName">File Name</a> | <a href="#log_logLevel">Log Level</a> | <a href="#log_debugLevel">Debug Level</a> | <a href="#log_rollingSize">Rolling Size (bytes)</a> | <a href="#log_keepDays">Keep Days</a> | <a href="#log_compressArchive">Compress Archive</a> | <a href="#log_enableStderrLog">Enable stderr Log</a> | <a href="#log_enableAioLog">Enable AIO Logging</a></p></section>
<section class="toc-row"><header>Access Log</header><p>
<a href="#accessLog_fileName">File Name</a> | <a href="#accessLog_pipedLogger">Piped Logger</a> | <a href="#accessLog_logFormat">Log Format</a> | <a href="#accessLog_logHeader">Log Headers</a> | <a href="#log_rollingSize">Rolling Size (bytes)</a> | <a href="#log_keepDays">Keep Days</a> | <a href="#log_compressArchive">Compress Archive</a></p></section>
</section>
<section><div class="helpitem"><article class="ls-helpitem"><div><header id="log_fileName"><h3>File Name<span class="ls-permlink"><a href="#log_fileName"></a></span><span class="top"><a href="#top">⇑</a></span></h3></header></div><h4>Description</h4><p>Specifies the path for the log file.</p> <h4>Syntax</h4><p>Filename which can be an absolute path or a relative path to $SERVER_ROOT.</p> <h4>Tips</h4><p><span title="Performance" class="ls-icon-performance"></span> Place the log file on a separate disk.</p> </article> </div>
<div class="helpitem"><article class="ls-helpitem"><div><header id="log_logLevel"><h3>Log Level<span class="ls-permlink"><a href="#log_logLevel"></a></span><span class="top"><a href="#top">⇑</a></span></h3></header></div><h4>Description</h4><p>Specifies the level of logging to include in your log file. Available levels (from high to low) are: <span class="val">ERROR</span>, <span class="val">WARNING</span>, <span class="val">NOTICE</span>, <span class="val">INFO</span> and <span class="val">DEBUG</span>. Only messages with level higher or equal to the current setting will be logged.</p> <h4>Syntax</h4><p>Select from drop down list</p> <h4>Tips</h4><p><span title="Performance" class="ls-icon-performance"></span> Using <span class="val">DEBUG</span> log level does not have any performance impact, unless <span class="tagl"><a href="#log_debugLevel">Debug Level</a></span> is set to a level other than <span class="val">NONE</span>. It's recommended to set Log Level to <span class="val">DEBUG</span> and Debug Level to <span class="val">NONE</span>. These settings mean that you will not fill up your hard disk with debug logging, but you will be able to use the <span class="tagl"><a href="ServerStat_Help.html#toggleDebugLog">Toggle Debug Logging</a></span> action to control debug output. This action can turn debug logging on and off on the fly, and is useful for debugging busy production servers.</p> <h4>See Also</h4><p class="ls-text-small"><span class="tagl"><a href="#log_debugLevel">Debug Level</a></span></p> </article> </div>
<div class="helpitem"><article class="ls-helpitem"><div><header id="log_debugLevel"><h3>Debug Level<span class="ls-permlink"><a href="#log_debugLevel"></a></span><span class="top"><a href="#top">⇑</a></span></h3></header></div><h4>Description</h4><p>Specifies the level of debug logging. <span class="tagl"><a href="#log_logLevel">Log Level</a></span> must be set to <span class="val">DEBUG</span> to use this feature. Debug logging is disabled when "Debug Level" is set to <span class="val">NONE</span> even if <span class="tagl"><a href="#log_logLevel">Log Level</a></span> is set to <span class="val">DEBUG</span>. <span class="tagl"><a href="ServerStat_Help.html#toggleDebugLog">Toggle Debug Logging</a></span> can be used to control debug level on a live server without restarting.</p> <h4>Syntax</h4><p>Select from drop down list</p> <h4>Tips</h4><p><span title="Performance" class="ls-icon-performance"></span> Important! Always set this to <span class="val">NONE</span> if you do not need detailed debug logging. Active debug logging will severely degrade service performance and potentially saturate disk space in a very short time. Debug logging includes detailed information for each request and response.<br/><br/> It's recommended to set Log Level to <span class="val">DEBUG</span> and Debug Level to <span class="val">NONE</span>. These settings mean that you will not fill up your hard disk with debug logging, but you will be able to use the <span class="tagl"><a href="ServerStat_Help.html#toggleDebugLog">Toggle Debug Logging</a></span> action to control debug output. This action can turn debug logging on and off on the fly, and is useful for debugging busy production servers.</p> <h4>See Also</h4><p class="ls-text-small"><span class="tagl"><a href="#log_logLevel">Log Level</a></span>, <span class="tagl"><a href="ServerStat_Help.html#toggleDebugLog">Toggle Debug Logging</a></span></p> </article> </div>
<div class="helpitem"><article class="ls-helpitem"><div><header id="log_rollingSize"><h3>Rolling Size (bytes)<span class="ls-permlink"><a href="#log_rollingSize"></a></span><span class="top"><a href="#top">⇑</a></span></h3></header></div><h4>Description</h4><p>Specifies when the current log file needs to be rolled over, also known as log rotation. When the file size is over the rollover limit, the active log file will be renamed to log_name.mm_dd_yyyy(.sequence) in the same directory and a new active log file will be created. The actual size of the rotated log file once it is created will sometimes be a little bigger than this size limit. Set to <span class="val">0</span> to disable log rotation.</p> <h4>Syntax</h4><p>Integer number</p> <h4>Tips</h4><p><span title="Information" class="ls-icon-info"></span> Append "K", "M", "G" to the number for kilo-, mega- and giga- bytes.</p> </article> </div>
<div class="helpitem"><article class="ls-helpitem"><div><header id="log_keepDays"><h3>Keep Days<span class="ls-permlink"><a href="#log_keepDays"></a></span><span class="top"><a href="#top">⇑</a></span></h3></header></div><h4>Description</h4><p>Specifies how many days the access log file will be kept on disk. Only rotated log files older than the specified number of days will be deleted. The current log file will not be touched regardless how many days worth of data it contains. If you do not want to auto-delete stale and very old log files, set this to <span class="val">0</span>.</p> <h4>Syntax</h4><p>Integer number</p> </article> </div>
<div class="helpitem"><article class="ls-helpitem"><div><header id="log_compressArchive"><h3>Compress Archive<span class="ls-permlink"><a href="#log_compressArchive"></a></span><span class="top"><a href="#top">⇑</a></span></h3></header></div><h4>Description</h4><p>Specifies whether to compress rotated log files in order to save disk space.</p> <h4>Syntax</h4><p>Select from radio box</p> <h4>Tips</h4><p><span title="Information" class="ls-icon-info"></span> Log files are highly compressible and this is recommended to reduce disk usage for old logs.</p> </article> </div>
<div class="helpitem"><article class="ls-helpitem"><div><header id="log_enableStderrLog"><h3>Enable stderr Log<span class="ls-permlink"><a href="#log_enableStderrLog"></a></span><span class="top"><a href="#top">⇑</a></span></h3></header></div><h4>Description</h4><p>Specifies whether to write to log when receiving stderr output from processes started by the server.<br/><br/> If enabled, stderr messages will be logged in the same directory as the server log with the fixed name "stderr.log". If disabled, all stderr output will be discarded.<br/><br/> Functions like PHP's error_log() which do not write directly to stderr (file handle 2) are not affected by this setting and will write to the file set in PHP ini directive 'error_log' or the server's "error.log" file with tag '[STDERR]' if that directive is not set.</p> <h4>Syntax</h4><p>Select from radio box</p> <h4>Tips</h4><p><span title="Information" class="ls-icon-info"></span> Turn it on if you need to debug configured external applications: i.e. PHP, Ruby, Java, Python, Perl.</p> </article> </div>
<div class="helpitem"><article class="ls-helpitem"><div><header id="log_enableAioLog"><h3>Enable AIO Logging<span class="ls-permlink"><a href="#log_enableAioLog"></a></span><span class="top"><a href="#top">⇑</a></span></h3></header></div><h4>Description</h4><p>Specifies whether to enable AIO logging for server log and access log. If enabled, asynchronous I/O will be used for writing log messages.</p> <h4>Syntax</h4><p>Select from radio box</p> <h4>Tips</h4><p><span title="Performance" class="ls-icon-performance"></span> Enabling AIO logging can help overall server performance when server I/O wait is high.</p> </article> </div>
<div class="helpitem"><article class="ls-helpitem"><div><header id="accessLog_fileName"><h3>File Name<span class="ls-permlink"><a href="#accessLog_fileName"></a></span><span class="top"><a href="#top">⇑</a></span></h3></header></div><h4>Description</h4><p>The access log filename.</p> <h4>Syntax</h4><p>Filename which can be an absolute path or a relative path to $SERVER_ROOT.</p> <h4>Tips</h4><p><span title="Performance" class="ls-icon-performance"></span> Put access log file on a separate disk.</p> </article> </div>
<div class="helpitem"><article class="ls-helpitem"><div><header id="accessLog_pipedLogger"><h3>Piped Logger<span class="ls-permlink"><a href="#accessLog_pipedLogger"></a></span><span class="top"><a href="#top">⇑</a></span></h3></header></div><h4>Description</h4><p>Specifies the external application that will receive the access log data sent by LiteSpeed through a pipe on its STDIN stream (file handle is 0). When this field is specified, the access log will be sent only to the logger application and not the access log file specified in previous entry.<br/><br/> The logger application must be defined in <span class="tagP"><a href="#ExtApp_Help">External Apps</a></span> section first. Server-level access logging can only use an external logger application defined at the server level. Virtual host-level access logging can only use a logger application defined at the virtual host level.<br/><br/> The logger process is spawned in the same way as other external (CGI/FastCGI/LSAPI) processes. This means it will execute as the user ID specified in the virtual host's <span class="tagl"><a href="VirtualHosts_Help.html#setUidMode">External App Set UID Mode</a></span> settings and will never run on behalf of a privileged user. <br/><br/> LiteSpeed web server performs simple load balancing among multiple logger applications if more than one instance of a logger application is configured. LiteSpeed server always attempts to keep the number of logger applications as low as possible. Only when one logger application fails to process access log entries in time will the server attempt to spawn another instance of the logger application. <br/><br/> If a logger crashes, the web server will start another instance but the log data in the stream buffer will be lost. It is possible to lose log data if external loggers cannot keep up with the speed and volume of the log stream.</p> <h4>Syntax</h4><p>Select from drop down list</p> </article> </div>
<div class="helpitem"><article class="ls-helpitem"><div><header id="accessLog_logFormat"><h3>Log Format<span class="ls-permlink"><a href="#accessLog_logFormat"></a></span><span class="top"><a href="#top">⇑</a></span></h3></header></div><h4>Description</h4><p><span class="tag">Enterprise Edition Only</span> Specifies the log format for the access log. When log format is set, it will override the <span class="tagl"><a href="#accessLog_logHeader">Log Headers</a></span> setting.</p> <h4>Syntax</h4><p>String. The syntax of log format is compatible with Apache 2.0's custom <a href="http://httpd.apache.org/docs/current/mod/mod_log_config.html#formats" target="_blank" rel="noopener noreferrer">log format</a>.</p> <h4>Example</h4><div class="ls-example"><b>Common Log Format (CLF)</b><br/> "%h %l %u %t \"%r\" %>s %b"<br/><br/> <b>Common Log Format with Virtual Host</b><br/> "%v %h %l %u %t \"%r\" %>s %b"<br/><br/> <b>NCSA extended/combined log format</b><br/> "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-agent}i\" <br/><br/> <b>Log cookie value of Foobar</b><br/> "%{Foobar}C"</div><h4>See Also</h4><p class="ls-text-small"><span class="tagl"><a href="#accessLog_logHeader">Log Headers</a></span></p> </article> </div>
<div class="helpitem"><article class="ls-helpitem"><div><header id="accessLog_logHeader"><h3>Log Headers<span class="ls-permlink"><a href="#accessLog_logHeader"></a></span><span class="top"><a href="#top">⇑</a></span></h3></header></div><h4>Description</h4><p>Specifies whether to log HTTP request headers: <span class="val">Referer</span>, <span class="val">UserAgent</span>, and <span class="val">Host</span>.</p> <h4>Syntax</h4><p>Select from checkbox</p> <h4>Tips</h4><p><span title="Performance" class="ls-icon-performance"></span> Turn this off if you do not need these headers in the access log.</p> <h4>See Also</h4><p class="ls-text-small"><span class="tagl"><a href="#accessLog_logFormat">Log Format</a></span></p> </article> </div>
</section>
</article><div class="ls-col-1-1"><footer class="copyright">Copyright © 2003-2020. <a href="https://www.litespeedtech.com">LiteSpeed Technologies Inc.</a> All rights reserved.</footer>
</div></div>
</body>
</html>
