This is the third in a series of newsletters that attempts to paint the picture of the forthcoming perfect storm relative to the ability of IT organizations to manage application performance (Compare Web Site Application and Performance Management products). The point of these newsletters is not to throw up roadblocks to the implementation of some really exciting and beneficial technologies. The point is to drive home the point that now is the time to make plans for how to manage what will otherwise be an unmanageable mess.

A lot of the value proposition for virtualization involves dramatic cost savings and hence is compelling. Storage virtualization vendors (Compare Storage Virtualization products), for example, talk about increasing storage utilization from around 15% to around 80%. That kind of an increase in storage utilization leads to cost savings that can be very appealing to senior management.

There is also a compelling value proposition for deploying a service-oriented architecture (SOA) based on the use of Web services. The basic idea behind an SOA is not new. From a technical perspective, the idea is that IT would develop reusable software modules that would easily interact with each other. From a business perspective, a Web service is not reusable software, but reusable components of a business process that can be plugged together like tinker toys to create new business processes quickly.

The movement to an SOA based on the use of Web services represents the next step in the development of distributed computing. To understand why the movement to Web services-based applications will drastically complicate the task of ensuring acceptable application performance, consider the typical 3-tier application architecture that is so common today. In a 3-tier application the application server(s) and the database server(s) typically reside in the same data center. As a result, the impact of the WAN is constrained to a single traffic flow, that being the flow between the user's Web browser and the application server.

In a Web services-based application, the Web services that comprise the application typically run on servers that are housed within multiple data centers. In many instances, at least some of these Web services reside in data centers owned by a company’s partners, customers and suppliers. As a result, the IT organization has little insight into, or control over, what is happening in those data centers. In addition, the WAN impacts multiple traffic flows and hence has a greater overall impact on the performance of a Web services-based application than it does on the performance of an n-tier application.

Steve Taylor is president of Distributed Networking Associates and publisher/editor-in-chief of Webtorials. Jim Metzler is vice president of Ashton, Metzler & Associates.