Enabling GZIP Compression in Apache on Ubuntu & Debian

GZIP compression is a powerful tool that can significantly improve website performance by reducing the size of files transferred between the web server and client. In this article, we will explore what GZIP compression is, why it matters, and how to enable it on Apache running on Ubuntu.

What is GZIP compression?

GZIP compression is a method of compressing files before sending them over the network. It works by analyzing the content of a file and finding patterns that can be replaced with shorter symbols, reducing the overall size of the file. When the client receives the compressed file, it decompresses it and displays the original content.

Why does GZIP compression matter?

Reducing the size of files transferred over the network can significantly improve website performance. Smaller files mean faster transfer times, which can result in quicker page load times and a better user experience. Additionally, GZIP compression can reduce bandwidth usage and lower hosting costs, especially for websites with high traffic.

Enabling GZIP compression on Apache

Enabling GZIP compression on Apache is a straightforward process. Here are the steps to follow:

1. Check if GZIP is already enabled: Before enabling GZIP, check if it’s already enabled on your Apache server by running the following command:

   sudo apache2ctl -t -D DUMP_MODULES | grep deflate 
   

   If GZIP is already enabled, you will see the following output:

   Output
   deflate_module (shared)
   

   If you don’t see this output, you need to enable the deflate module, which is responsible for handling GZIP compression.

2. Enable the deflate module: To enable the deflate module, run the following command:

   sudo a2enmod deflate 
   

   This command will create a symbolic link to the deflate configuration file in the /etc/apache2/mods-enabled/ directory.

3. Configure GZIP compression: Once the deflate module is enabled, you need to configure GZIP compression in the Apache configuration file. Open the configuration file using your preferred text editor.

   sudo nano /etc/apache2/apache2.conf 
   

   To enable it for specific website, edit the site specific virtual host configuration file or create a .htaccess file under the document root. Then add/append the following snippet to the file.

   <IfModule mod_deflate.c> # Compress HTML, CSS, JavaScript, Text, XML and fonts AddOutputFilterByType DEFLATE application/javascript AddOutputFilterByType DEFLATE application/rss+xml AddOutputFilterByType DEFLATE application/vnd.ms-fontobject AddOutputFilterByType DEFLATE application/x-font AddOutputFilterByType DEFLATE application/x-font-opentype AddOutputFilterByType DEFLATE application/x-font-otf AddOutputFilterByType DEFLATE application/x-font-truetype AddOutputFilterByType DEFLATE application/x-font-ttf AddOutputFilterByType DEFLATE application/x-javascript AddOutputFilterByType DEFLATE application/xhtml+xml AddOutputFilterByType DEFLATE application/xml AddOutputFilterByType DEFLATE font/opentype AddOutputFilterByType DEFLATE font/otf AddOutputFilterByType DEFLATE font/ttf AddOutputFilterByType DEFLATE image/svg+xml AddOutputFilterByType DEFLATE image/x-icon AddOutputFilterByType DEFLATE text/css AddOutputFilterByType DEFLATE text/html AddOutputFilterByType DEFLATE text/javascript AddOutputFilterByType DEFLATE text/plain AddOutputFilterByType DEFLATE text/xml # Level of compression (highest compression level) DeflateCompressionLevel 9 # Do not compress certain file types SetEnvIfNoCase Request_URI \.(?:gif|jpe?g|png)$ no-gzip dont-vary SetEnvIfNoCase Request_URI \.(?:exe|t?gz|zip|bz2|sit|rar)$ no-gzip dont-vary SetEnvIfNoCase Request_URI \.pdf$ no-gzip dont-vary # Make sure proxies don't deliver the wrong content Header append Vary User-Agent env=!dont-vary </IfModule>

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   <IfModule mod_deflate.c>   # Compress HTML, CSS, JavaScript, Text, XML and fonts   AddOutputFilterByType DEFLATE application/javascript   AddOutputFilterByType DEFLATE application/rss+xml   AddOutputFilterByType DEFLATE application/vnd.ms-fontobject   AddOutputFilterByType DEFLATE application/x-font   AddOutputFilterByType DEFLATE application/x-font-opentype   AddOutputFilterByType DEFLATE application/x-font-otf   AddOutputFilterByType DEFLATE application/x-font-truetype   AddOutputFilterByType DEFLATE application/x-font-ttf   AddOutputFilterByType DEFLATE application/x-javascript   AddOutputFilterByType DEFLATE application/xhtml+xml   AddOutputFilterByType DEFLATE application/xml   AddOutputFilterByType DEFLATE font/opentype   AddOutputFilterByType DEFLATE font/otf   AddOutputFilterByType DEFLATE font/ttf   AddOutputFilterByType DEFLATE image/svg+xml   AddOutputFilterByType DEFLATE image/x-icon   AddOutputFilterByType DEFLATE text/css   AddOutputFilterByType DEFLATE text/html   AddOutputFilterByType DEFLATE text/javascript   AddOutputFilterByType DEFLATE text/plain   AddOutputFilterByType DEFLATE text/xml     # Level of compression (highest compression level)   DeflateCompressionLevel 9     # Do not compress certain file types   SetEnvIfNoCase Request_URI \.(?:gif|jpe?g|png)$ no-gzip dont-vary   SetEnvIfNoCase Request_URI \.(?:exe|t?gz|zip|bz2|sit|rar)$ no-gzip dont-vary   SetEnvIfNoCase Request_URI \.pdf$ no-gzip dont-vary     # Make sure proxies don't deliver the wrong content   Header append Vary User-Agent env=!dont-vary </IfModule>

   The above configuration file includes a list of file types that should be compressed and the level of compression (9 being the highest compression level). It also specifies file types that should not be compressed, such as images and archives, as compressing these types of files can actually increase their size.

4. Restart Apache: After configuring GZIP compression, you need to restart Apache to apply the changes:

   sudo systemctl restart apache2 
   

Verify Gzip Compression

Now that your site has been enabled with gzip compression, let’s use one of below online tools to verify that Gzip is working correctly.

• http://www.whatsmyip.org/http-compression-test/

Conclusion

Enabling GZIP compression on Apache running on Ubuntu is an effective way to improve website performance and reduce bandwidth usage. By following the steps outlined in this article, you can easily enable GZIP compression and enjoy the benefits of faster website loading times and improved user experience.