"The Majority Rules !"
In a nutshell, you have Quorum if you have the majority.
Quorum is the number of "operational" nodes in a cluster that are required to control the resources, modify the cluster definition, or perform certain cluster operations.
The main goals of quorum operations:
- identify who has the majority when a cluster is broken up into sub-clusters
- keep data consistent, especially when shared file systems are being used
- protect critical resources … maintain HA control