Microsoft® Windows Server™ 2003 White Paper
able to access the session state.
The right platform won’t force you to change operating systems to achieve scalability, nor will it force you into a corner by mandating a particular scaling mode, such as scale up. The Windows Server 2003 family of products supports different scaling modes, allowing you to mix and match as your needs change. Windows Server 2003 offers the same manageability features across the entire product line, so administrator skills transfer well as applications are scaled up or out, even scaled down. Your scalability solution remains your decision, independent of the operating system or hardware platform.
If response time is faster than necessary under typical or even peak load, you may be able to reduce costs by scaling “down” or “in” instead of “up” and “out.” For example, scaling an application that is running in a large data center to run on fewer machines can be thought of as “scaling in” (the opposite of scaling out). Scaling in might reduce hardware costs in an overbuilt data center or when setting up a secondary data center with lesser throughput needs. For example, if a large company acquires a smaller company and wants to deploy the same applications in a secondary data center that demands lesser throughput, the same application could be run on a cluster of, say, two machines instead of ten.
As distributed computing increases, running applications on smaller systems is also important. This is where the ability to “scale down” (the opposite of scaling up) an application server is important. Scaling an application down can be important for both smaller organizations and lightweight clients. For example, the .NET Framework allows developers to write one application that runs on Windows Server 2003, Enterprise Edition and also on small servers at satellite offices such as branch banks. That is, an application originally deployed to a data center can also be deployed to the desktop. The .NET Framework also supports devices such as PDAs (using the .NET Compact Framework) and cell phones (using the Mobile Internet Toolkit ).
Implementing a Scalable Architecture4