Oracle Real Application Cluster(RAC) is an oracle database component(option) and the architecture of the cluster is based on a share everything architecture.
On Oracle RAC database, there will be multiple clusters of RAC database instances that have independent memory and background process but share the same storage and operate as a single system. The datafiles, controlfiles, redo log files and SPFILES of the clustered nodes are stored on the shared disks.
And Oracle RAC provides High availability incase of failure of cluster instances and scalability & load balancing purposes.
Ezana Edited answer 17/04/2022