{"id":13818,"date":"2019-04-06T09:45:24","date_gmt":"2019-04-06T09:45:24","guid":{"rendered":"http:\/\/www.appservgrid.com\/paw92\/?p=13818"},"modified":"2019-04-06T09:45:24","modified_gmt":"2019-04-06T09:45:24","slug":"5-tips-to-boost-the-performance-of-your-apache-web-server","status":"publish","type":"post","link":"https:\/\/www.appservgrid.com\/paw92\/index.php\/2019\/04\/06\/5-tips-to-boost-the-performance-of-your-apache-web-server\/","title":{"rendered":"5 Tips to Boost the Performance of Your Apache Web Server"},"content":{"rendered":"

According to\u00a0a recent report by Netcraft<\/a>\u00a0(a well-known Internet company that provides among other services web browser usage statistics),\u00a0Apache<\/strong>\u00a0continues to be the most widely used web server among sites and Internet-facing computers.<\/p>\n

\n

\"Improve<\/a><\/p>\n

5 Tips to Boost Your Apache Web Server Performance<\/p>\n<\/div>\n

Additionally,\u00a0Apache<\/strong>\u00a0keeps experiencing the largest growth among the top web servers, followed by\u00a0Nginx<\/strong>\u00a0and\u00a0IIS<\/strong>. Thus, if you are a system administrator in charge of managing Apache installations, you need to know how to make sure your web server performs at the best of its capacity according to your (or you client\u2019s) needs.<\/p>\n

In this article we will discuss a few tips that will help you ensure that Apache will run smoothly and be able to handle the number of requests you are expecting from remote clients.<\/p>\n

However, please keep in mind that Apache was not designed with the objective of setting benchmark records \u2013 but, even so, it is still capable of providing high performance in almost any usage case you can possibly think of.<\/p>\n

\u200bTIP #1: Always keep Apache updated to its latest version<\/h3>\n

It goes without saying that having the latest version of Apache installed is probably one of the first things you need to consider. As of November 19, 2015, the latest version of Apache available in the\u00a0CentOS 7<\/strong>\u00a0repositories is\u00a02.4.6<\/strong>, whereas in\u00a0Debian\u2019s<\/strong>\u00a0is\u00a02.4.10<\/strong>.<\/p>\n

However, there may be a recent improvement or a bug fix that has been added to a newly-released stable version, which is then made available to download and install from source. Compilation and installation instructions are also provided\u00a0here<\/a>\u00a0\u2013 just remember that if you choose this update method, you may want to back up your current configuration files \/ sites \/ virtual hosts as a precaution.<\/p>\n

In any event, you can check your currently installed version as follows:<\/p>\n

# httpd -v               [On RedHat\/CentOS based systems]\r\n# apache2 \u2013v             [On Debian\/Ubuntu based systems] \r\n<\/pre>\n
\n
\"Check<\/a><\/p>\n
Check Apache Version<\/p>\n<\/div>\n
As a rule of thumb, stick with the update method provided by the package manager of your chosen distribution (yum update httpd<\/code>\u00a0or\u00a0aptitude safe-upgrade apache2<\/code>, for CentOS or Debian, respectively) unless there is no other way. You can read the latest release notes in the\u00a0Apache Documentation section<\/a>\u00a0in the Apache HTTP server Project website.<\/p>\n
TIP #2: If you are using a Kernel older than 2.4, consider upgrading now<\/h3>\n
Why? Kernel versions\u00a02.4<\/strong>\u00a0and above have the sendfile kernel system call enabled by default. That, in turn, facilitates high performance network file transfers (which are desired in the context of web server-client communications) and enables Apache to deliver static content faster and with lower CPU utilization by performing simultaneous read and send operations.<\/p>\n
You can view your currently installed kernel with:<\/p>\n
# uname -r\r\n<\/pre>\n
and compare it to the latest stable kernel in www.kernel.org (4.3 at the time of this writing).<\/p>\n
\n
\"Check<\/a><\/p>\n
Check Linux Kernel Version<\/p>\n<\/div>\n
Although it is a process not intended for beginners, upgrading your kernel is an interesting exercise to learn more about the internals of Linux.<\/p>\n
\u200bTIP #3: Choose the Multi-Processing Module (MPM) that works best for your case<\/h3>\n
In practice,\u00a0MPMs<\/strong>\u00a0extend the modular functionality of Apache by allowing you to decide how to configure the web server to bind to network ports on the machine, accept requests from clients, and use children processes (and threads, alternatively) to handle such requests.<\/p>\n
Beginning with version 2.4, Apache offers three different MPMs to choose from, depending on your needs:<\/p>\n
    \n
  1. \n
      \n
    1. The\u00a0prefork<\/code>\u00a0MPM uses multiple child processes without threading. Each process handles one connection at a time without creating separate threads for each. Without going into too much detail, we can say that you will want to use this MPM only when debugging an application that uses, or if your application needs to deal with, non-thread-safe modules like mod_php.<\/li>\n
    2. The\u00a0worker<\/code>\u00a0MPM uses several threads per child processes, where each thread handles one connection at a time. This is a good choice for high-traffic servers as it allows more concurrent connections to be handled with less RAM than in the previous case.<\/li>\n<\/ol>\n<\/li>\n<\/ol>\n
        \n
      1. Finally, the\u00a0event<\/code>\u00a0MPM is the default MPM in most Apache installations for versions 2.4 and above. It is similar to the worker MPM in that it also creates multiple threads per child process but with an advantage: it causes\u00a0KeepAlive<\/strong>\u00a0or\u00a0idle<\/strong>\u00a0connections (while they remain in that state) to be handled by a single thread, thus freeing up memory that can be allocated to other threads. This MPM is not suitable for use with non-thread-safe modules like\u00a0mod_php<\/strong>, for which a replacement such a\u00a0PHP-FPM<\/strong>\u00a0must be used instead.<\/li>\n<\/ol>\n
        To check the\u00a0MPM<\/strong>\u00a0used by your Apache installation, you can do:<\/p>\n
        # httpd -V\r\n<\/pre>\n
        The image below show that this particular web server is using the\u00a0prefork MPM<\/strong>.<\/p>\n
        \n
        \"Check<\/a><\/p>\n
        Check Apache MPM<\/p>\n<\/div>\n
        To change this, you will need to edit:<\/p>\n
        # \/etc\/httpd\/conf.modules.d\/00-mpm.conf          [On RedHat\/CentOS based systems]\r\n# \/etc\/apache2\/mods-available\/<mpm>.load   [On Debian\/Ubuntu based systems]\r\n<\/pre>\n
        Where <mpm> can be\u00a0mpm_event<\/strong>,\u00a0mpm_worker<\/strong>, or\u00a0mpm_prefork<\/strong>.<\/p>\n
        and uncomment the line that loads the desired module like so:<\/p>\n
        LoadModule mpm_event_module modules\/mod_mpm_event.so\r\n<\/pre>\n
        Note<\/strong>: To make the event MPM work in Debian, you may have to install the\u00a0libapache2-mod-fastcgi<\/strong>\u00a0package from the non-free repositories.<\/p>\n
        Additionally, for CentOS you will need\u00a0php-fpm<\/strong>\u00a0(along with\u00a0fcgi<\/strong>\u00a0and\u00a0mod_fcgid<\/strong>) whereas in Debian it\u2019s called\u00a0php5-fpm<\/strong>\u00a0(along with\u00a0apache2-mpm-event<\/strong>).<\/p>\n
        Last, but not least, restart the web server and the newly installed\u00a0php-fpm<\/strong>\u00a0(or\u00a0php5-fpm<\/strong>) service:<\/p>\n
        On RedHat\/CentOS<\/h4>\n
        # systemctl restart httpd php-fpm && systemctl enable httpd php-fpm\r\n<\/pre>\n
        On Debian\/Ubuntu<\/h4>\n
        # systemctl restart apache2 php5-fpm && systemctl enable apache2 php5-fpm\r\n<\/pre>\n
        Although you can set Apache to use a specific MPM, that configuration can be overridden on a\u00a0per-virtual host<\/a>basis in the same fashion as indicated earlier.<\/p>\n
        Just drop the corresponding tags into the configuration file for each virtual host and you\u2019re ready to go \u2013 but make sure you\u2019re using one and only one MPM per vhost.<\/p>\n
        Finally, please note that regardless of your chosen distribution,\u00a0php-fpm<\/strong>\u00a0relies on the implementation of\u00a0FastCGI<\/strong>, which is the reason why I recommended the additional package installations earlier.<\/p>\n
        For more details and examples on\u00a0php-fpm<\/strong>\u00a0and how it can along with the event MPM increase the performance of Apache, you should refer to\u00a0the official documentation<\/a>.<\/p>\n
        This is what I see after changing the default MPM from prefork to event in the same box shown in the previous image:<\/p>\n
        \n
        \"Choose<\/a><\/p>\n
        Choose Apache MPM Module<\/p>\n<\/div>\n
        In\u00a0CentOS 7<\/strong>, you will need to make sure that the\u00a0http<\/strong>\u00a0and\u00a0https<\/strong>\u00a0services are enabled through the firewall, and that the network interface(s) are properly added to the default zone.<\/p>\n
        For example:<\/p>\n
        # firewall-cmd --zone=internal --add-interface=tun6to4 \r\n# firewall-cmd --zone=internal --add-interface=tun6to4 --permanent \r\n# firewall-cmd --set-default-zone=internal \r\n# firewall-cmd --add-service=http \r\n# firewall-cmd --add-service=https \r\n# firewall-cmd --add-service=http --permanent \r\n# firewall-cmd --add-service=https --permanent \r\n# firewall-cmd --reload\r\n<\/pre>\n
        The reason why I\u2019m bringing this up is because I recently experienced an issue where the default\u00a0firewalld configuration<\/a>\u00a0settings in a cloud VPS prevented\u00a0php-fpm<\/strong>\u00a0and Apache from processing php files.<\/p>\n
        As a basic test (I am sure you can think of more complicated or stressful ones), I will create a php file that checkes the existence of another file named\u00a0test.php<\/code>\u00a0in the same directory of two CentOS 7 servers with the same hardware characteristics and load but with different MPM. One of them will use event and the other one will use prefork:<\/p>\n
        \n
        \"Compare<\/a><\/p>\n
        Compare Apache Event and Prefork Module<\/p>\n<\/div>\n
        This is the php code that I\u2019ve saved into a file named\u00a0checkiffileexists.php<\/code>:<\/p>\n
        <?php\r\n$filename = 'test.php';\r\n\r\nif (file_exists($filename)) {\r\n    echo \"The file $filename exists\";\r\n} else {\r\n    echo \"The file $filename does not exist\";\r\n}\r\n?>\r\n<\/pre>\n
        Then we will run the\u00a0Apache benchmark tool (ab)<\/a>\u00a0with\u00a0200<\/strong>\u00a0simultaneous requests until\u00a02000<\/strong>\u00a0requests are completed:<\/p>\n
        # ab -k -c 100 -n 2000 localhost\/checkiffileexists.php\r\n<\/pre>\n
        Let\u2019s run the test and compare the results. Pay attention to the performance statistics:<\/p>\n
        \n
        \"Apache<\/a><\/p>\n
        Apache Performance Load Testing<\/p>\n<\/div>\n
        As you can see, the performance of the server with event is highly superior to its\u00a0prefork<\/strong>\u00a0counterpart in every aspect of this test.<\/p>\n
        TIP #4: Allocate RAM wisely for Apache<\/h3>\n
        Perhaps the most critical hardware item to be taken into account is the amount of\u00a0RAM<\/strong>\u00a0allocated for each Apache process. While you cannot control this directly, you can restrict the number of child processes through the\u00a0MaxRequestWorkers<\/strong>\u00a0directive (formerly known as\u00a0MaxClients<\/strong>\u00a0in Apache\u00a02.2<\/strong>), which will put limits on the RAM usage by Apache. Again, you can set this value on a per host or per virtual host basis.<\/p>\n
        To do this, you should take note of the average amount of RAM used by Apache, then multiply it by the number of\u00a0MaxRequestWorkers<\/strong>, and that is the amount of memory that will be allocated for Apache processes. One thing you never want your web server to do is to begin using swap, as that will significantly decrease its performance. Thus, you should always keep the usage of RAM by Apache within the limits that you can afford and never rely on swap for it.<\/p>\n
        For example, the following block will restrict the number of simultaneous clients to\u00a030<\/strong>. If more clients hit the host, they may experience a delay or a momentary failure that can be easily solved by refreshing the browser. While this may be considered undesirable, it is healthier for the server and in the long run, best for your site as well.<\/p>\n
        You can place this block inside\u00a0\/etc\/httpd\/conf\/httpd.conf<\/code>\u00a0or\u00a0\/etc\/apache2\/apache2.conf<\/code>, depending on whether you are using CentOS or Debian.<\/p>\n
        Please note that the same principle applies to all\u00a0MPMs<\/strong>\u00a0\u2013 I am using event here to continue with the concept outlined in the previous tip:<\/p>\n
        <IfModule mpm_event_module>\r\n    StartServers 3\r\n    MinSpareThreads          25\r\n    MaxSpareThreads          75\r\n    ThreadLimit                      64\r\n    ThreadsPerChild          25\r\n    MaxRequestWorkers    30\r\n    MaxConnectionsPerChild    1000\r\n<\/IfModule>\r\n<\/pre>\n
        In any event, it is highly recommended that you refer to the\u00a0Apache 2.4 docs<\/a>\u00a0to see which directives are allowed for your chosen MPM.<\/p>\n
        \u200bTIP #5: Know your applications<\/h3>\n
        As a rule of thumb, you should not load any Apache modules that are not strictly needed for your application to work. This will require at least an overall knowledge of the applications running on your server, specially if you are a system administrator and there\u2019s another team in charge of development.<\/p>\n
        You can list the currently loaded modules with:<\/p>\n
        # httpd -M          [On RedHat\/CentOS based systems]\r\n# apache2ctl -M     [On Debian\/Ubuntu based systems]\r\n<\/pre>\n
        To unload \/ disable modules in\u00a0CentOS<\/strong>, you will need to comment out the line that begins with\u00a0LoadModule<\/strong>(either in the main configuration file or in an auxiliary one inside\u00a0\/etc\/httpd\/conf.modules.d<\/strong>.<\/p>\n
        On the other hand,\u00a0Debian<\/strong>\u00a0provides a tool called\u00a0a2dismod<\/strong>\u00a0to disable modules and is used as follows:<\/p>\n
        # a2dismod module_name\r\n<\/pre>\n
        To enable it back:<\/p>\n
        # a2enmod module_name\r\n<\/pre>\n
        In either case, remember to restart Apache for the changes to take effect.<\/p>\n
        \u200b Summary<\/h3>\n
        In this article we have reviewed\u00a05 tips<\/strong>\u00a0that will help you tune the Apache web server and increase its performance. In addition, you should remember that optimization and performance without security is pointless, so you may want to refer to the\u00a0install mod_pagespeed to improve webserver performance<\/a>\u00a0and\u00a0Apache hardening tips article<\/a>\u00a0in Tecmint.com as well.<\/p>\n
        Since we cannot adequately cover all the aspects of this topic in this article, perhaps you will think of other ideas that you would like to share with the rest of the community. If so, feel free to let us know using the comment form below.<\/p>\n
        Source<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"
        According to\u00a0a recent report by Netcraft\u00a0(a well-known Internet company that provides among other services web browser usage statistics),\u00a0Apache\u00a0continues to be the most widely used web server among sites and Internet-facing computers. 5 Tips to Boost Your Apache Web Server Performance Additionally,\u00a0Apache\u00a0keeps experiencing the largest growth among the top web servers, followed by\u00a0Nginx\u00a0and\u00a0IIS. Thus, if you … <\/p>\n
        Continue reading “5 Tips to Boost the Performance of Your Apache Web Server”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-13818","post","type-post","status-publish","format-standard","hentry","category-linux"],"_links":{"self":[{"href":"https:\/\/www.appservgrid.com\/paw92\/index.php\/wp-json\/wp\/v2\/posts\/13818","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.appservgrid.com\/paw92\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.appservgrid.com\/paw92\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.appservgrid.com\/paw92\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.appservgrid.com\/paw92\/index.php\/wp-json\/wp\/v2\/comments?post=13818"}],"version-history":[{"count":1,"href":"https:\/\/www.appservgrid.com\/paw92\/index.php\/wp-json\/wp\/v2\/posts\/13818\/revisions"}],"predecessor-version":[{"id":13819,"href":"https:\/\/www.appservgrid.com\/paw92\/index.php\/wp-json\/wp\/v2\/posts\/13818\/revisions\/13819"}],"wp:attachment":[{"href":"https:\/\/www.appservgrid.com\/paw92\/index.php\/wp-json\/wp\/v2\/media?parent=13818"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.appservgrid.com\/paw92\/index.php\/wp-json\/wp\/v2\/categories?post=13818"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.appservgrid.com\/paw92\/index.php\/wp-json\/wp\/v2\/tags?post=13818"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}