HP Integrity rx5670 Windows Integrity Cluster Installation and Configuration G - Page 9

Introduction Server Cluster vs. Network Load Balancing Table 1-1 Server Cluster vs. Network Load Balancing Windows Server 2003 provides two types of clustering services: • Server Cluster-Available only in Windows Server 2003, Enterprise Edition or Datacenter Edition, this service provides high availability and scalability for mission-critical applications such as databases, messaging systems, and file and print services. The servers (nodes) in the cluster remain in constant communication. If one of the nodes becomes unavailable as a result of failure or maintenance, another node immediately begins providing service, a process known as failover. Users accessing the service continue to access it, unaware that it is now being provided from a different node. Both Windows Server 2003, Enterprise Edition and Datacenter Edition support server cluster configurations of up to 8 nodes. • Network Load Balancing (NLB)-Available in all editions of Windows Server 2003, this service load balances incoming Internet Protocol (IP) traffic across clusters. NLB enhances both the availability and scalability of Internet server-based programs such as Web servers, streaming media servers, and Terminal Services. By acting as the load balancing infrastructure and providing control information to management applications built on top of Windows Management Instrumentation (WMI), NLB can seamlessly integrate into existing Web server farm infrastructures. NLB clusters can scale to 32 nodes. Table 1-1 summarizes some of the differences between these two technologies. Additional differences and considerations are detailed in the following sections. Server Cluster vs. Network Load Balancing Server Cluster NLB Used for databases, e-mail services, line of business (LOB) applications, and custom applications Included with Windows Server 2003, Enterprise Edition, and Windows Server 2003, Datacenter Edition Provides high availability and server consolidation Can be deployed on a single network or geographically distributed Supports clusters up to eight nodes Requires the use of shared or replicated storage Used for Web servers, firewalls, and Web services Included with all four versions of Windows Server 2003 Provides high availability and scalability Generally deployed on a single network but can span multiple networks if properly configured Supports clusters up to 32 nodes Doesn't require any special hardware or software; works "out of the box" Chapter 1 9