1)what is Clusterware software?

*The Clusterware software provides the basic clustering services at the operating system level that enable any specific software to run on the clustering node.

*The software which requires installing in order to make multiple machines into one single machine.


2)How does it work?

*It can be installed independently to administer any cluster environment

*The Rac software is installed on Oracle grid (Clusterware)

*For the Clusterware daemons run on each node if we won't installed on the every node that node won't be a part of the cluster

*Oracle Clusterware is installed on separate home is called "grid Home"

*Oracle Clusterware would administer the node as well as Oracle database instances running on each node.


3)What Oracle Clusterware administers?

* It provides

1)All the nodes which are part of the cluster

2)High Availability

3)Cluster scale up and scale down

4)Global resource management


Note: The Clusterware is managed anything is called resource i.e. database, Ip, instance, application process etc



4)Hardware components:

*One or more servers

*Two Network components- 1 public IP and 1 private IP

*Shared storage

*Each cluster node had own local hard disk which is used to store OS and oracle binaries

*The own copy of Oracle binaries in each node that it increases high availability
i.e if one node oracle binaries would corrupt it won't affect the other nodes in the cluster


5)Software Components:

I)Voting disk:

*This file contains the list of nodes which is part of the cluster.

*Whenever we start the cluster each member will go voting disk and mark itself as part of the cluster

*If the node is not able to start, it won't be a part of the cluster

*It resides in the shared storage because to avoid a single point of failure.

Example: it like an attendance register to maintain the records every day who are all present and absence details


*it has the list of all the nodes and every resource of cluster manages

*OCR store cluster configuration information

*Oracle uses OCR to store information about the components that Oracle Clusterware controls like oracle RAC databases,
listeners, VIPs and services

*we can have upt0 5 OCR locations and it must reside on shared storage

Ex: it is like an employee register it 'll maintain the records of no of employees who are working in
that organization, personnel details, and Qualifications.