..: Importance of running orainstRoot.sh' and root.sh script:

Thursday 2 March 2017

Creates the inventory pointer file (/etc/oraInst.loc),This file shows the inventory location and group it is linked to.
Changes groupname of the oraInventory directory to oinstall group.

Creates a /etc/oratab file.This is the file which we use to make automatic Database shutdown and startup.
Sets the Oracle base and home environments.
It Modifies the ownership to 'root' user on the Oracle base and Cluster home filesystem.
Configures the OCR and voting disks (only on the first node)
Sets an appropriate permission to the OCR base directory
Generates OCR keys for the 'root' user.
Creates the OCR backup and Network Socket directories , also takes ocr backup to a default location
Starts the Clusterware daemons and also add daemons to the inittab file.
Verifies whether the Clusterware is up on all nodes.
Verifies the super user privileges.
Creates a trace directory
Creates and configures an ASM instance and starts up the instance.
Creates required ASM disk groups, if ASM is being used to put OCR and voting files.
Creates the voting disk file also Displays it's details
Stops and restarts a cluster stack and other cluster resources on the local node
Updates the Oracle inventory file.

When 'root.sh' is executed on the last node of the cluster,

Sets Oracle base and home environmental variables.
/etc/oratab file will be created
Performs the super user privileges verification.
Adds trace directories
It Generates OCR keys for the 'root' user.
Adds a daemon to inittab
Starts the Oracle High Availability Service Daemon (OHASD) process.
Stops/starts a cluster stack and other cluster resources on the local node
initiates ./vipca in silent mode to configure nodeapps such as, GSD, VIP, and ONS for all the nodes.
Performs a backup of the OCR file
Updates the Oracle inventory file.
Completes with UpdateNodeList success operation.

..