IBM 86655RY Hardware Maintenance Manual - Page 185

Introduction to IBM ServeRAID cluster solution A cluster is a type of parallel or distributed system that consists of interconnected computers that are used as a single, unified computing resource. In other words, a group of computers linked together in such a way that they share and manage a set of resources that can support a number of users at the same time. This high-availability clustering solution is based on a two-server cluster, where both servers can access the same storage devices, but only one server at a time controls the storage devices shared by both servers. If one of the two running server fails, the surviving server automatically assumes control of the shared resources managed by the failed server while still controlling its own resources at the same time. The failed server can then be repaired offline without the loss of time or work efficiency because the shared data and applications earlier managed by the failed server are still online to the clients. When the failed server is operational again, it can be placed back into the cluster; the resources are reallocated between the two servers and the cluster resumes normal operations. A controller is a device that coordinates and controls the operation of one or more input and output devices, such as workstations, and synchronizes the operation of such devices with the operation of a system as a whole. IBM ServeRAID Cluster Solution, as discussed in this book, uses the IBM ServeRAID4x Ultra160 SCSI controller. IBM ServeRAID Cluster Solution also uses IBM expansion enclosures, such as the following: • IBM Netfinity EXP15 Rack Expansion Enclosure • IBM Netfinity EXP200 Rack Expansion Enclosure • IBM Netfinity EXP300 Rack Expansion Enclosure You can install IBM ServeRAID Cluster Solution by using one of the following software applications: • Microsoft Cluster Service, which is part of Windows NT Server Enterprise Edition • Microsoft Cluster Service using Windows 2000, which is part of Windows 2000 Advanced Server Edition or Windows 2000 Datacenter Server Edition • Vinca High Availability for Novell IntranetWare, which is part of the IBM Netfinity Cluster Pack by Vinca • Novell High Availability Server 1.0 The following figure shows an example of a detailed view of a cluster. Installing and configuring ServeRAID controllers 175