Google released a new product, mod_pagespeed. It is a mod for Apache web server.
mod_pagespeed is an open-source Apache module that automatically optimizes web pages and resources on them. It does this by rewriting the resources using filters that implement web performance best practices. Webmasters and web developers can use mod_pagespeed to improve the performance of their web pages when serving content with the Apache HTTP Server.
mod_pagespeed includes several filter that optimize JavaScript, HTML and CSS stylesheets. It also includes filters for optimizing JPEG and PNG images. The filters are based on a set of best practices known to enhance web page performance. Webmasters who set up mod_pagespeed in addition to configuring proper caching and compression on their Apache distribution should expect to see an improvement in the loading time of the pages on their websites.
To install it on Centos 5.5, I did following.
1) SSH to my VPS with root right.
2) Add Google Linux Software Repositories.
wget https://dl-ssl.google.com/linux/linux_signing_key.pub rpm --import linux_signing_key.pub
3) Install Pagespeed mod.
wget https://dl-ssl.google.com/dl/linux/direct/mod-pagespeed-beta_current_i386.rpm yum localinstall mod_pagespeed_*.rpm
4) Restart Apache.
service httpd restart
There are some configuration can help to handle the filter of mod_pagespeed.
at /etc/httpd/conf.d
file is pagespeed.conf
More details on how to use mod_pageSpeed, click here.
We tried it and found it improved performance by an average 20%, but only really affected the clumsily written pages. We did a little comparison here: http://townend.co/blog/google-pagespeed/