What is a Voting Disk?
- Voting disk is a file in which all the nodes of a cluster register their heartbeat information.
- It also contains the list of the active nodes.
- Voting disks or files are like attendance registers where nodes mark their attendance (heartbeats) to confirm they are alive.
- If the disk is not updated in a short timeout period, the node is considered unhealthy and may be rebooted to protect the database.
Example:
- 3 node clusters (Node1, Node2, Node3) are present in cluster ware.
- DB, Vote Disk and OCR Disk are present on Shared Storage.
- All three Nodes will register their heartbeats to voting disk
Query to check the status of Voting Disk
- Voting disk is created on shared storage
- It is created by oracle clusterware installation process
- OCR disk will also get created by clusterware installation process
- When any node is not able to send a heartbeat to the voting disk, then it will reboot itself.
- For high availability, Oracle recommends that you have a minimum of three voting disks.
- We must have an odd number of disks.
Query to check the status of cluster on all nodes
Query to check the cluster ware version
In the next blog we will discuss more about voting disk addition, removal, backup and how to recover voting disk in RAC.
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