Patent ID: 7051182

Claim:
A data processing system, comprising: a plurality of hosts; a plurality of data storage devices; and an apparatus coupling the hosts to the data storage devices, the apparatus having host ports connected to the hosts, wherein the data storage devices are configured into logical storage units, the apparatus is programmed with a mapping of the hosts to respective logical storage units, wherein 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, wherein one or more of the ports that provide access to the data storage are assigned to each host, a set of storage volumes are made accessible from each of the ports that provide access to the data storage, and the apparatus is programmed so that said each host can access storage at said each of the ports that provide access to the data storage only if said each of the ports that provide access to the data storage has been assigned to said each host; wherein the mapping includes a respective mapping for each host of logical unit numbers of storage to data storage volumes that are configured from the data storage devices and are accessible to said each host, and the apparatus is programmed to respond to a request directed to said each of the ports from said each host for a report of the logical unit numbers of storage that are accessible to said each host from said each of the ports that provide access to the data storage by providing a report of the logical unit numbers of storage that are accessible to said each host from said each of the ports that provide access to the data storage.