A storage virtualization system for accessing at least one storage device for a virtual logical unit (VLUN) from at least one host. The system includes at least one upstream processing element (UPE) which is adapted for coupling to a corresponding host server. The system is further adapted for coupling to at least one storage device. The controller also includes a primary central processing element (CPE) that can be configurably coupled to the UPEs. The primary CPE permits data transfer to occur between a host and a storage device via the corresponding UPE. The controller further includes a backup CPE that can be configurably coupled to the UPEs. The backup CPE is configurable to permit the data transfer when the primary CPE becomes unavailable.