To handle high traffic levels and deliver exceptional performance, web applications must include an integrated caching solution to keep the most commonly used data in memory. The Microsoft ASP.NET framework provides a basic caching solution. However, the basic caching solution is limited to a single web server because it has no built in capability to synchronize cache items across multiple web servers.
DotNetNuke includes an extra caching layer on top of ASP.NET. This extra layer allows web farm synchronization using a variety of approaches. The Community and Professional Editions both include a file system caching provider which relies on a specific web farm configuration that leverages a shared file server (SAN) to store cache files. DotNetNuke Professional Edition also includes a web service caching provider. The web service caching provider is beneficial for serious business applications because it enables use of a distributed web farm without the need for a shared file server. In addition, it is less resource intensive on the server and more efficient in terms of managing cache item expirations.