{"id":473387,"date":"2016-10-28T08:00:53","date_gmt":"2016-10-28T01:00:53","guid":{"rendered":"https:\/\/www.harianaceh.co.id\/?p=473387"},"modified":"2025-10-28T05:04:43","modified_gmt":"2025-10-27T22:04:43","slug":"apache-mpm-directives-explained-the-ultimate-performance-tuning-guide","status":"publish","type":"post","link":"https:\/\/www.harianaceh.co.id\/2016\/10\/28\/apache-mpm-directives-explained-the-ultimate-performance-tuning-guide\/","title":{"rendered":"Apache MPM Directives Explained: The Ultimate Performance Tuning Guide"},"content":{"rendered":"

BANDA ACEH<\/strong> – How directives behave and which directives are mainly available hinges on the loaded MPM<\/a>. As discussed in our previous series, MPM is short for MultiProcess Modules, and they determine the basis for how Apache<\/a> addresses multiprocessing. Using our last article on Apache MPM Modules as a springboard, we will use this section to cover the following subsections:<\/p>\n

Each part will focus on how the directives affect performance for their respective MPM and some common considerations that should be assessed when optimizing Apache with those specific MPMs.<\/p>\n

Be sure to review this article in its entirety as the universal directives operate in the same manner regardless of the MPM chosen.<\/p>\n

General Optimization<\/strong><\/h3>\n

IfModule<\/h4>\n

An important directive to learn when working with Apache servers is the IfModule conditional statement. There are two parts to the IfModule statement. A beginning, which also accepts a module name or module source file name, as well as a closing statement. When the provided module is loaded into Apache, then all directives between the beginning IfModule statement and the closing IfModule statement are also read into the Apache running configuration. Please review the provided example below for further clarification:<\/p>\n

<ifModule mpm_prefork_module>
\nMaxSpareServers 16
\n<\/ifModule>
\nTimeout 60
\n<\/code><\/p>\n

The above example defines the MaxSpareServers directive only when loaded by mpm_prefork_module. The Timeout directive is applied every time due to it being outside of the IfModule closing statement.<\/em><\/strong><\/p>\n

IfModule statements are used to maintain compatibility within Apache configuration between module changes. Maintaining compatibility is done by grouping directives into IfModule statements, so they are only used when the required module is loaded. Ensuring a syntactically correct configuration file even when swapping modules.<\/p>\n

Remember, as a rule of thumb, appropriately wrapping everything in an IfModule statement is a best practice standard with Apache and should be adhered to for superior compatibility in config files.<\/p>\n

Timeout<\/h4>\n

The numerical value of seconds Apache waits for all common I\/O events. Apache will abandon requests fail to complete before the provided\u00a0Timeout<\/em>\u00a0value.<\/p>\n

Determining the right\u00a0Timeout<\/em>\u00a0depends on both traffic habits and hosted applications. Ideally,\u00a0Timeout<\/em>\u00a0should be as low as possible while still allowing the vast majority of regular traffic to operate without issue. Large timeouts, those above 1 minute, open the server to\u00a0SlowLoris<\/a>\u00a0style DOS attacks and foster a long wait in the browser when it encounters a problem. Lower timeouts allow Apache to recover from errant stuck connections quickly. It becomes necessary to strike a balance between the two extremes.<\/p>\n

\"\"<\/a><\/figure>\n

Avoid increasing the global Timeout when addressing issues with a single script, or user, that requires a long Timeout. Problems can usually be resolved by a .htaccess file or include file to increase the Timeout directive for that specific script.<\/p>\n

KeepAlive<\/h4>\n
\n
\"KeepAlive\"<\/picture><\/a><\/figure>\n<\/div>\n

A simple on|off toggle enables the\u00a0KeepAlive<\/em>\u00a0protocols with supported browsers. The\u00a0KeepAlive<\/em>\u00a0feature can provide as much as a 50% reductions in latency, significantly boosting the performance of Apache.\u00a0KeepAlive<\/em>\u00a0accomplishes this by reusing the same initial connections a browser creates when connecting to Apache for all follow-up requests which occur within a short period.<\/p>\n

KeepAlive<\/em>\u00a0is a powerful feature and in general, should be enabled in most situations. It works great for reducing some of the CPU and Network overhead with modern element heavy websites. For example, an easy way to visualize\u00a0KeepAlive<\/em>\u00a0is with the \u201chold the door\u201d phrase. Imagine a queue of people entering a building through a single doorway. Each person is required to open the door, walk through it, then close the door before the next person does the same process. Mostly, that\u2019s how Apache works without\u00a0KeepAlive<\/em>. When enabled, the door stays open until all the people in line are through the door before it closes again.<\/p>\n

Two additional related directives also govern\u00a0KeepAlive<\/em>.\u00a0MaxKeepAliveRequests<\/a>\u00a0and\u00a0KeepAliveTimeout<\/a>. Discussed in the next section, each one plays a vital role in fine-tuning of the KeepAlive directive.<\/p>\n

MaxKeepAliveRequests<\/strong><\/h4>\n

Sets a limit on the number of requests an individual\u00a0KeepAlive<\/em>\u00a0connection is permitted to handle. Once reached, Apache forces the connection to terminate, and creates a new one for any additional requests.<\/p>\n

Determining an ideal setting here is open to interpretation. Generally, you want this value to be at least as high as the largest count of elements (HTML, Text, CSS, Images, Etc..) served by the most heavily trafficked pages on the server.<\/p>\n

\"\"<\/a><\/figure>\n

Set MaxKeepAliveRequests to double that of the largest count of elements on common pages. Services like\u00a0webpagetest.org<\/a>\u00a0or\u00a0gtmetrix.com<\/a>\u00a0can count elements on a page.<\/p>\n

KeepAliveTimeout<\/h3>\n

This directive is measured in seconds and will remain idle waiting for additional requests from its initiator. Since these types of connections are only accessible to their initiator, we want to keep\u00a0KeepAliveTimeout<\/em>\u00a0very low. A low value prevents too many\u00a0KeepAlive<\/em>\u00a0connections from locking out new visitors due to connection priority.<\/p>\n

\"\"<\/a><\/figure>\n

A large\u00a0MaxKeepAliveRequests<\/em>\u00a0directive with a very low\u00a0KeepAliveTimeout<\/em>\u00a0allows active visitors to reuse connections while also quickly recovering threads from idle visitors:<\/p>\n