What is oracle clusterware? What is the advantage of oracle clusterware?
Oracle Clusterware is a software that provides clustering features to RAC databases on a set of servers. It enables the cluster nodes, Oracle RAC instances, to communicate with each other and act as a one database server serving the database users.
RAC has two components named Oracle Grid Infrastructure and Oracle RAC. And oracle grid infrastructure combines oracle clusterware and oracle ASM. Oracle clusterware also has two components, oracle clusterware registry(OCR) and voting disk.
Oracle clusterware is installed separately on a nonshared oracle home and has dedicated Operating system user named “grid”. The grid user is the owner of the oracle grid infrastructure and oracle ASM instance.