(1) One of the four levels of service (fast, status, data high, or data low) that determines if a distribution is put on the normal or priority distribution queue.
(2) A set of logical characteristics of storage required by a data set managed by a storage management subsystem (SMS). Examples of these logical characteristics are performance, security, and availability.
(3) A class of service that can be used in business policies to aggregate a set of desired and implied service qualities.