An apparatus has host ports for coupling hosts to data storage devices. The data storage devices are configured into logical storage units, and the apparatus is programmed with a mapping of the hosts to respective logical storage units. The apparatus decodes a host identifier and a logical storage unit specification from each data access request received at each host port, and determines whether or not the decoded host identifier and logical storage unit specification are in conformance with the mapping in order to permit or deny data access of the logical storage unit through the host port. For example, the apparatus includes a switch for routing the data storage access requests from the host ports to ports that provide access to the data storage, and a set of logical volumes of storage are accessible from each of the ports that provide access to the data storage.