Storage virtualization subsystem and system with host-side redundancy via SAS connectivity

A storage virtualization system with host-side redundancy via SAS connectivity, comprising:

• at least one initiator for sending at least one I/O request;
• and
• at least one redundant storage virtualization subsystem using an SAS signal interconnect interface to couple to the initiator, each of the at least one redundant storage virtualization subsystem further comprising:
• a storage virtualization controller (SVC) pair including a first SVC and a second SVC for executing an I/O operation in response to an I/O request sent from the at least one 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;
• and
• a physical storage device (PSD) array comprising at least one PSD for providing storing space to the subsystem.

A storage virtualization subsystem with host-side redundancy via 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 I/O operation in response to an I/O request sent from the initiator, each of the first SVC and the second SVC having a built-in virtual SAS expander for providing each physical port with multiple virtual IDs;
• a switch component disposed on the path of an I/O device interconnect between the SVC pair and the initiator;
• and
• a physical storage device (PSD) array, including at least one PSD for providing the storage virtualization subsystem with storing space;
• wherein the signal interconnect interface between the SVC pair and the initiator is an SAS interface.