This read-only string reports the specific subclass of a cluster event, such as ESC_cluster_node_state_change, ESC_cluster_rg_state, or ESC_cluster_quorum_state_change, drawn from a defined set of Solaris Cluster event subclasses. Admins use it as the primary way to identify exactly what kind of cluster event occurred, since eventClassName itself is always the same generic value. For example, seeing ESC_cluster_rg_state here identifies this specific event as a resource group state change, prompting the admin to check which resource group and what its new state is via the associated attribute table.