Oracle 19c - Oracle 19c RAC | Real Application Clusters (RAC) Technical Architecture Overview Part1

June 23, 2021  

In this video discussed all about Oracle 19c Real Application Clusters Technical Architecture Overview. Oracle Database can be configured in two basic ways: as a single instance (SI) database (non-cluster) or a Real Application Clusters (RAC) database (Cluster). A Single Instance (SI) database has the Oracle software, database files, memory and processes all on one server. (link to database technical architecture diagram). A single instance database has a one-to-one relationship between the instance (memory and processes) and the database (database files). Oracle RAC environments, however, have a one-to-many relationship between the database and instances. An Oracle RAC database can have up to 100 instances, all of which access one database. All the servers for a single database in the Oracle RAC environment must belong to the same Oracle Real Application Clusters. A Real Application Clusters (RAC) Database has multiple database Instances hosted on a RAC Cluster. These instances access a single set of Database files on Shared Storage. Frequently the Shared storage is provided by an ASM instance local to the node hosting the RAC database instance. In Oracle ASM 19c there is only one configuration option, that is Flex ASM, Flex ASM can have a variety of placements for the ASM instances in the cluster that is controlled by setting the cardinality, the number of ASM instances, in the cluster. The Standalone Cluster consists of one or more cluster nodes configured with locally available shared storage, a private interconnect, local instances of Automatic Storage Management (ASM) for managing that shared storage, and the GI Management Repository (GIMR) for storing cluster health and diagnostic information. An Extended Cluster is a special case of a standalone cluster where the nodes of the cluster are in two or more sites at different locations. Cheers! Ramesh.