Overview of Planning for High Availability and Scalability
Updated: March 28, 2003
Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2
A highly available system reliably provides an acceptable level of service with minimal downtime. Downtime penalizes businesses, which can experience reduced productivity, lost sales, and lost faith from clients, partners, and customers.
By implementing recommended IT practices, you can increase the availability of key services, applications, and servers. These practices also help you minimize both planned downtime, such as for maintenance or service pack installations, and unplanned downtime, such as downtime caused by a server failure.
Additionally, the clustering technologies available in Windows Server 2003 can provide added levels of availability and scalability. A cluster is a group of independent computers that work together to provide a common set of services. If a cluster node (a computer in a cluster) fails, other nodes in the cluster assume the functions of the failed node. Clusters enhance the availabilityof critical applications and services. Clusters also increase the scalabilityof your deployment by allowing you to scale your solution over time to support additional clients or increased client demands. In most deployments, server clustersprovide availability, and Network Load Balancing clustersincrease scalability.
If you need the highest levels of availability (and if your budget can accommodate the expense), use both recommended IT practices and clustering for a truly comprehensive high availability deployment that is also scalable. If you determine that your organization needs to increase availability and scalability, this chapter can help you create an effective plan for implementing a high availability and scalability solution that meets your organization’s current and future needs.
Server clusters are supported by the Microsoft® Windows® Server 2003, Enterprise Edition, and Windows® Server 2003, Datacenter Edition, operating systems. Network Load Balancing is supported by all Windows Server 2003 operating systems, including Windows® Server 2003, Standard Edition, and Windows® Server 2003, Web Edition.