Patent ID: 8255737

Claim:
A storage system comprising: a storage controller configured to access data stored in a storage subsystem; the storage subsystem including a storage device having n ports, wherein n is an integer greater than one, and wherein the storage device is configured to store the data and to make the data available to the storage controller via each of the n ports; and a communication fabric configured to couple the storage controller to each of the n ports of the storage device via m paths, wherein m is an integer greater than n, so that the storage system is configured to tolerate failure in up to m−1 paths through the communication fabric, such that the data in the storage device remains accessible to the storage controller even in the presence of failure in up to m−1 paths of the m paths, and wherein the communication fabric includes: a horizontal expander coupling the storage controller to the storage subsystem, a first vertical expander of the storage subsystem coupling the horizontal expander to the storage device, wherein the first vertical expander couples a plurality of links in the communication fabric to one of the n ports of the storage device, and a second vertical expander, wherein the horizontal expander is configured to enforce a zone for isolating the first vertical expander from the second vertical expander of the storage system.