Sun Cluster 3.1 Concepts Guide

Cluster Configuration Repository (CCR)

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.

Caution – Caution –

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.