Ensuring the Availability of Applications and Services
Ensuring the Availability of Applications and Services |
|
A cluster is a group of independent computers that work together to run a common set of applications or services and provide the image of a single system to the client and application. Clustered computers are physically connected by cables and programmatically connected by cluster software. These connections allow computers to use problem-solving features, such as load balancing and failover, that are not available for use with stand-alone computers.
Load balancing distributes server loads across all configured servers and prevents one server from being overworked. This, in turn, enables you to increase your capacity incrementally to meet demand. Failover provides constant support to users by automatically transferring resources from a failing or offline cluster server to a functioning one. This provides cluster users with constant access to the resources. Windows Clustering currently provides the following two clustering technologies:
Network Load BalancingNetwork Load Balancing provides scalability and high availability of TCP/IP-based applications and services, by combining up to 32 servers running Windows 2000 Advanced Server into a single, load balancing cluster. The most common use for Network Load Balancing is to distribute incoming Web requests among its cluster of Internet server applications (such as Internet Information Services applications).
Cluster Service Using Advanced Server, Cluster service lets you combine two servers to work together as a server cluster to ensure that mission-critical applications and resources remain available to clients. Server clusters enable users and administrators to access certain resources of the servers, or nodes, as a single system rather than as separate computers.
When you are planning and deploying applications and services for high availability, it is critical that you define best practices for your organization. Microsoft has developed a series of best practice guides for high availability. For more information about these guides, see the Microsoft TechNet High Availability link on the Web Resources page at http://windows.microsoft.com/windows2000/reskit/webresources.