Patent ID: 8352653

Claim:
A storage virtualization subsystem with host-side redundancy via serial-attached Small Computer System Interface (SAS) connectivity connected to at least one initiator, the subsystem comprising: a storage virtualization controller (SVC) pair including a first SVC and a second SVC for executing an Input/Output (I/O) operation in response to an I/O request sent from the initiator, wherein each SVC of the SVC pair comprises at least one I/O device interconnect controller and the I/O device interconnect controller has at least one host-side port for coupling to the initiator; at least one SAS expander disposed on the path of an I/O device interconnect between the SVC pair and the initiator for providing the device expansion function comprising addressing and routing; and a physical storage device (PSD) array comprising at least one PSD for providing storing space to the subsystem; wherein the signal interconnect interface among the SVC pair, the SAS expander, and the initiator is a SAS interface.