The shared disk array is configured to allow all nodes access to the disk resources, but with only one node actively processing data. Comprised of one or more servers (nodes). An architecture that provides redundancy through a configuration in which other servers essentially act as clones of the main production system. This configuration allows seamless failover capabilities in the event of a CPU, memory, or other hardware failure that does not affect storage. Allows two or more database servers to stay, "in sync" so that the secondary servers can answer queries and potentially actually change data. If data on the secondary servers is changed. it is merged during synchronization. Can be used to allow "slices" of a database to be cloned between several sites. The 'slice" can be a set of database objects (i.e. tables) or even parts of a table, such as only certain specific rows (horizontal slicing) or only certain columns. A technology for making data available offsite and to consolidate data to central sites Can be used for high availability or for dimaster recoverability..