When we decided to give our website a brand new look, we also evaluated whether to change Content Management Systems and decided to migrate our content management system to Concrete 5 from DotNetNuke.  DotNetNuke had served us well, but we wanted to move to a more modern and lightweight framework with a better administrative interface.   This migration presented us with a few challenges to overcome.

While we redesigned our company website, we didn’t want to wait to launch it until we had migrated all of our product websites to Concrete 5.   To combine the two systems under one domain name, we leveraged Varnish as a proxy to split requests between our LAMP stack hosting Concrete 5 and our Windows server hosting DotNetNuke.    We’ve found Varnish to be a robust and yet lightweight tool for proxying, caching, and load balancing.  You can read more about how we used Varnish to host Walkshed on Amazon Web Services in this related blog post.

Another concern when migrating CMS’s is making sure that the old URLs continue to function and issue the right redirects to users and search engines.   Andrew Jennings took this project on and whipped up a URL redirection system for us using Apache’s mod_rewrite module.

• As requests come into Varnish, we first test to see if Concrete5 can respond to the URL.
• If Concrete5 isn’t managing the content for the URL, the request bounces into our redirection system that maps old URLs to new URLs using a binary hashtable and issues 301 permanent redirects to the client.   We found that this approach is faster than simply relying on Apache .htaccess files since we have several thousand legacy URLs to support.
• If the URL request is not in the mapping file, we simply forward the request to the Windows server to be served by DotNetNuke.
• If DotNetNuke returns a 404 error, we redirect the request back to Concrete 5 to respond with a 404 error so that our redirection is invisible to the user.

A final goal of the CMS migration was to improve page load times for our visitors.   Having pages that load quickly not only improves the experience for our web visitors, but also has an impact on search engine rankings.    Concrete5 suggested we setup Alternative PHP Cache (APC) to speed up the pages it is serving, which has definitely improved performance on our new pages.

We found a great WordPress plugin (which runs our blogs) that can also leverage APC called W3 Total Cache.   It provides a host of other functionality that we’re exploring including HTML, JS, and CSS minification as well as pushing design assets to Amazon’s CDN.

I always find it amusing how something as straight forward as a new website launch has so much happening behind the scenes.   To find out more about the content that went into the new Azavea website read Rachel’s related blog post.