HP OpenVMS Guide to System Security: OpenVMS Version 8.4 > Chapter 12 Securing a Cluster
A single security domain is one in which each cluster member must make the same access control decision when presented with a particular user's access request for a particular object. The operating system provides this level of protection for files, queues, and other cluster-visible objects such as devices, disk and tape volumes, and resource domains. “Summary of Object Behavior in a Cluster” summarizes the behavior of each object class and explains where each stores security profiles. See “Descriptions of Object Classes”Chapter 5 for a description of each object class.