{"id":796,"date":"2021-07-23T12:38:22","date_gmt":"2021-07-23T12:38:22","guid":{"rendered":"https:\/\/ssdsunucum.com\/blog\/apache-vs-php-fpm-bottleneck-with-child-processes\/"},"modified":"2021-07-23T12:38:22","modified_gmt":"2021-07-23T12:38:22","slug":"apache-vs-php-fpm-bottleneck-with-child-processes","status":"publish","type":"post","link":"https:\/\/ssdsunucum.com\/blog\/apache-vs-php-fpm-bottleneck-with-child-processes\/","title":{"rendered":"Apache vs. PHP-FPM Bottleneck with Child Processes"},"content":{"rendered":"<\/p>\n
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<\/div>\n
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Overview<\/h2>\n

Apache servers that use the prefork<\/code> MPM with fewer server instances than the maximum number of PHP-FPM child processes may experience performance issues. This document explains how to resolve these dependency issues.<\/p>\n

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Important:<\/div>\n
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This issue and solution only<\/strong> apply to servers that run Apache\u2019s prefork<\/code> MPM.<\/p>\n<\/p><\/div>\n<\/div>\n

The issue<\/h2>\n

In the following scenario, the PHP-FPM server\u2019s configuration allows a maximum of 20 PHP-FPM child processes and the Apache server\u2019s configuration allows five server instances.<\/p>\n

The following example represents the PHP-FPM server\u2019s configuration file:<\/p>\n

\n
\n\n\n
\n
1\n<\/span>2\n<\/span>3\n<\/span><\/code><\/pre>\n<\/td>\n
\n
_is_present: 1<\/span>\npm_max_children: 20<\/span>\npm_max_requests: 20<\/span><\/code><\/pre>\n<\/td>\n<\/tr>\n<\/table>\n<\/div>\n<\/div>\n
The following example represents the Apache server\u2019s configuration file:<\/p>\n
\n
\n\n\n
\n
1\n<\/span>2\n<\/span>3\n<\/span>4\n<\/span>5\n<\/span><\/code><\/pre>\n<\/td>\n
\n
StartServers: 5<\/span>\n<IfModule prefork.c>\nMinSpareServers: 10<\/span>\nMaxSpareServers: 10<\/span>\n<\/IfModule><\/code><\/pre>\n<\/td>\n<\/tr>\n<\/table>\n<\/div>\n<\/div>\n
If the Apache server receives 20 requests, it immediately passes ten of those requests to the available PHP-FPM child processes. After PHP-FPM processes those requests, Apache will pass another ten requests to PHP-FPM.<\/p>\n
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Warning:<\/div>\n
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For high-volume servers, this configuration can cause severe performance issues.<\/p>\n<\/p><\/div>\n<\/div>\n
The solution<\/h2>\n
To solve this issue, you must<\/strong> configure Apache to allow enough server instances to handle the maximum number of PHP-FPM child processes. To do this, configure the following options in WHM\u2019s Global Configuration<\/em> interface (WHM >> Home >> Service Configuration >> Global Configuration<\/em>):<\/p>\n
    \n
  • \n
    Minimum Spare Servers<\/em><\/p>\n<\/li>\n
  • \n
    Maximum Spare Servers<\/em><\/p>\n<\/li>\n
  • \n
    Max Request Workers<\/em><\/p>\n<\/li>\n<\/ul>\n
    Set these options to a value greater than or equal to the pm_max_children<\/code> setting in the PHP-FPM server\u2019s configuration file.<\/p>\n<\/p><\/div>\n","protected":false},"excerpt":{"rendered":"
    Overview Apache servers that use the prefork MPM with fewer server instances than the maximum number of PHP-FPM child processes may experience performance issues. This document explains how to resolve these dependency issues. Important: This issue and solution only apply to servers that run Apache\u2019s prefork MPM. The issue In the following scenario, the PHP-FPM …<\/p>\n","protected":false},"author":1,"featured_media":797,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[1],"tags":[],"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/ssdsunucum.com\/blog\/wp-json\/wp\/v2\/posts\/796"}],"collection":[{"href":"https:\/\/ssdsunucum.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ssdsunucum.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ssdsunucum.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ssdsunucum.com\/blog\/wp-json\/wp\/v2\/comments?post=796"}],"version-history":[{"count":0,"href":"https:\/\/ssdsunucum.com\/blog\/wp-json\/wp\/v2\/posts\/796\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/ssdsunucum.com\/blog\/wp-json\/wp\/v2\/media\/797"}],"wp:attachment":[{"href":"https:\/\/ssdsunucum.com\/blog\/wp-json\/wp\/v2\/media?parent=796"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ssdsunucum.com\/blog\/wp-json\/wp\/v2\/categories?post=796"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ssdsunucum.com\/blog\/wp-json\/wp\/v2\/tags?post=796"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}