Definition of irrigation. 1  1 : the therapeutic flushing of a body part with a stream of liquid. 2  2 : the watering of land by artificial means to foster plant growth.
Answer: To start with, Oracle Real Application Clusters (RAC) are a database system involving a configuration of multiple hosts or servers joined together with clustering software and accessing the shared disk storage structures.
Oracle RAC allows multiple computers to run Oracle RDBMS software simultaneously while accessing a single database, thus providing clustering. In a non-RAC Oracle database, a single instance accesses a single database. The database consists of a collection of data files, control files, and redo logs located on disk.