Patent ID: 7631143

Claim:
A data storage system, comprising: a plurality of front-end controllers for interfacing the data storage system to host computers; a plurality of back-end controllers; a cache and interconnect block coupled between the front-end controllers and the back-end controllers, the cache and interconnect block including (1) a cache memory for temporarily storing data blocks being transferred between the data storage system and the host computer, and (2) interconnect circuitry operative to provide interconnections among the front-end controllers, the cache memory, and the back-end controllers; and a plurality of disk enclosures coupled to the back-end controllers, each disk enclosure including: a pair of backplanes; a plurality of physical disk drives having respective reliability measures, each physical disk drive being redundantly connected to both of the backplanes; a pair of power supplies, each power supply being redundantly connected to each of the backplanes; and a pair of first controllers coupled by the backplanes to the plurality of physical disk drives in a redundant fashion to enable each first controller to access any of the plurality of physical disk drives, the first controllers being operative to utilize the physical disk drives to implement a set of virtual disk drives in a first redundant-array-of-independent-disks (RAID) configuration such that each virtual disk drive has a reliability measure greater than the respective reliability measures of the physical disk drives; wherein each back-end controller is a second controller coupled to the first controllers of a corresponding disk enclosure and operative to utilize the virtual disk drives of the corresponding disk enclosure to implement a set of storage volumes in a second RAID configuration such that each storage volume has a reliability measure greater than the respective reliability measures of the virtual disk drives of the corresponding disk enclosure.