The Cluster Configuration Repository (CCR) is a private, cluster-wide database for storing information pertaining to the configuration and state of the cluster. The CCR is a distributed database. Each node maintains a complete copy of the database. The CCR ensures that all nodes have a consistent view of the cluster “world.” To avoid corrupting data, each node needs to know the current state of the cluster resources.
The CCR uses a two-phase commit algorithm for updates: An update must complete successfully on all cluster members or the update is rolled back. The CCR uses the cluster interconnect to apply the distributed updates.
Although the CCR consists of text files, never edit the CCR files manually. Each file contains a checksum record to ensure consistency between nodes. Manually updating CCR files can cause a node or the entire cluster to stop functioning.
The CCR relies on the CMM to guarantee that a cluster is running only when quorum is established. The CCR is responsible for verifying data consistency across the cluster, performing recovery as necessary, and facilitating updates to the data.