Scale ASP.NET Apps Through Distributed Caching

By Iqbal Khan

ASP.NET has become a highly popular technology for developing Web applications. A large number of these ASP.NET applications need to scale to accommodate the growing number of transactions and traffic they support.

During the client/server era, scalability wasn't really a concern because there weren't that many concurrent users. Today, with Web technologies, you can easily have hundreds of thousands of users, which causes issues with data storage.

ASP.NET architecture allows applications to scale by adding more Web servers in a load-balanced Web farm. However, in ASP.NET, data storage is not very scalable when it comes to handling a growing number of transactions. As a result, if you increase the transaction load, the data storage starts to slow down and eventually grinds to a halt.

Reducing Bottlenecks

In an ASP.NET application, data storage usually means either the application database or the ASP.NET Session State storage -- and herein lie application-scalability bottlenecks, as shown in Figure 1. The application database is normally a relational database, such as SQL Server or another relational database. ASP.NET Session State storage is one of the three options that Microsoft provides -- namely InProc, State Server or SQLServer modes. In all of these storage options, scalability is a major issue. I'll explain this in more detail later in this article.