In sweet memories of my ever loving brother "kutty thambi " ARUN KUMAR

Saturday, December 26, 2009

Administering Voting Disks in Oracle Real Application Clusters

The Oracle Clusterware is comprised primarily of two components: the voting disk and the OCR (Oracle Cluster Registry). The voting disk is nothing but a file that contains and manages information of all the node memberships and the OCR is a file that manages the cluster and RAC configuration. Let's take a quick look at administering the voting disks

Administering voting disks

Backup and Recovery:

First, let's look at backing up the voting disks by running the following command:

dd if=voting_disk_name of=backup_file_name
dd if=/dev/sdc1 of=/tmp/votingdisk_bkp
2088387+0 records in
2088387+0 records out
1069254144 bytes (1.1 GB) copied, 889.716 seconds, 1.2 MB/s

This operation needs to be performed on all voting disks. Here, clearly you see that the if (input file) is the source file (replace the voting_disk_name with your voting disk) and the of (output file) is the destination backup file containing all information of the voting disk contents. Type dd –help for more information. Running the command with the names of the files reversed will help you recover your voting disk file(s).

dd if=backup_file_name of=voting_disk_name

before restore, stop the crs with the following command:
[root@rac1 bin]# /etc/init.d/ stop

You can use the ocopy command in Windows environments or use the crsctl commands to copy and administer the files. Also, note that if you have multiple voting disks, which are not abnormal to have, you can use the crsctl command to add and delete the voting disks. For instance:

crsctl delete css votedisk path

Here you delete the disk and the path, which is the complete path of the location of the file, and below you add your new or backup files by doing the following:

crsctl add css votedisk path

This way you can either statically or dynamically add or remove your voting disks in your RAC.

You must, however, note that if your cluster is down, then you can use the -force option

crsctl add css votedisk path -force

to modify the voting disk configuration. This way you don’t end up interfering with other Clusterware daemons. Using it in your active configuration may corrupt your configuration.


rajeshkumar g

No comments: