web| Server | Network to improve the reliability of Web sites and increase site capacity, we deployed four Network Load Balancing (NLB) Web servers, one of two clustering technologies in the Windows 2000 operating system. As a follow-on product of the Windows NT Server 4.0 Enterprise Edition of Microsoft Windows NT® Load Balancing Service (WLBS), NLB supports up to 32 nodes in a load-balanced cluster and makes all nodes work as one server.
Let's discuss this in detail below.
NLB allocates incoming IP traffic in a server group (cluster) consisting of servers that provide TCP/IP services. It uses a common virtual IP address for the entire cluster and transparently assigns client requests to multiple servers in the cluster. Each server in the cluster can handle a predetermined proportional load, or distribute the load evenly across all servers (we use this approach).
One of the servers in the cluster may fail or be taken offline due to regular maintenance and system upgrades. In this case, NLB automatically assigns the load to the remaining servers in order to ensure uninterrupted service to incoming client requests.
If site traffic increases, NLB can easily add more WEB servers to the NLB cluster to increase capacity for additional load. To extend a Web server farm, more than 32 nodes, NLB can be used in conjunction with other load balancing technologies, such as Round-robin DNS (RRDNS). In fact, many organizations have used this load-balancing combination-NLB and RRDNS-to extend their Web farm with hundreds of, or even thousands of, servers.
For more information about how these load balancing technologies work and how to set up Network Load Balancing Web servers, see the article build a highly reliable and scalable Web farm.
Order Processing Server
In the workflow of most electronic transaction sites, there are often operations that can be run asynchronously, such as orders and fulfillment orders. Making certain operations of a Web application run asynchronously can make Web applications more responsive by reducing contention for resources on the Web server. The results can improve site usage, scalability, reliability, and availability.
To support asynchronous operations, you use Windows Advanced Server and Microsoft Message Queuing (MSMQ).
