Could you please provide cluster startup sequence in Oracle RAC.
Thank you :)
The operating system reads the /etc/init.d file via the initialization daemon named init or init.d once it begins and finishes the boot scrap process. The oracle high availability service daemon is triggered by the init tab file.
OHASD is started by platform-specific procedures, such as init.d in Linux, when a node in an Oracle Clusterware cluster starts up. Oracle Clusterware is started by launching OHASD. The Oracle Local Registry (OLR) is kept on the local file system, and OHASD has access to it. OLR supplies the data required to finish OHASD startup.
GPNPD and CSSD are mentioned by OHASD ( Cluster synchronization Service Daemon ). The GPNP Profile is kept on the local file system, and CSSD has access to it. The following bootstrap data is included in this profile:
a. Diskgroup Discovery String in ASM
b. Location of the ASM SPFILE (Diskgroup name)
c. The name of the ASM Diskgroup in which the Voting Files are stored.
CSSD can access the locations of the Voting Files on ASM Disks using well-known references in the ASM Disk headers, allowing CSSD to finish the initialization and establish or join an existing cluster.
With CSSD setup and running, OHASD launches an ASM instance, and ASM may now work. If the ASM SPFILE is placed in a Diskgroup, the ASM instance utilises a special code to locate its contents.
CRSD has access to Clusterware's OCR after an ASM instance is running and its Diskgroups are mounted.
CRSD is started by OHASD with access to an ASM Diskgroup's OCR.
Clusterware completes the startup process and takes control of other services.
This command will display the status of all cluster resources:
$ ./crsctl status resource -t
For Oracle CRSCTL Commands List visit our support link mentioned below: