Windows Server 2008 supports two different kinds of high-availability clustering, both of which can greatly improve your fault tolerance:
For many TCP/IP-based applications, the Network Load Balancing service provides a simple, "shared nothing," fault-tolerant application server.
Server clusters provide a highly available fault-tolerant environment that can run applications, provide network services, and distribute loads. Server clusters are available only with Windows Server 2008, Enterprise Edition and Windows Server 2008, Datacenter Edition.
The Network Load Balancing service allows TCP/IP-based applications to be spread dynamically across up to 32 servers. If a particular server fails, the load and connections ...