Patent ID: 7574542

Claim:
A data storage system, comprising: (A) a first chassis having therein: (a) a pair of storage processors; (b) a pair of SAS expander having a bidirectional front end port and a plurality of bidirectional backend ports, and an expansion port; (c) a pair of SAS controller each one being coup between a corresponding one of the pair of processors and a corresponding one of the pair of the expanders; (d) a first plurality of multiplexers, each one of the multiplexers having: (i) a pair of bidirectional front end ports; (ii) a pair of bidirectional back end ports; wherein (iii) a first one of the pair of bidirectional front end ports is connected to a corresponding backend port of a corresponding one of the pair of SAS expanders; and (iv) a second one of the pair of bidirectional front end ports is connected to a corresponding backend port of a corresponding one of the pair of SAS expanders; and (e) a plurality of disk drives, each one being coupled to at least one backend port of a corresponding one of the first plurality of multiplexers; (B) a second chassis having therein; (a) a pair of SAS expanders, each one of the pair of SAS expanders having a bidirectional front end expansion port and a bidirectional backend expansion port; (b) an second plurality of multiplexers, each one of the second plurality of multiplexers having: (i) a pair of bidirectional front end ports; (ii) a pair of bidirectional back end ports; wherein (iii) a first one of the pair of bidirectional front end ports is connected to a corresponding backend port of a corresponding one of the pair of SAS expanders in the second chassis; and (iv) a second one of the pair of bidirectional front end ports is connected to a corresponding backend port of a corresponding one of the pair of SAS expanders disposed in the second chassis; and (c) a second plurality of disk drives, each one being coupled to at least one backend port of a corresponding one of the second plurality of multiplexers; and (d) wherein: (i) the bidirectional front end expansion port of a first one of the pair of SAS expanders is connected to only the expansion port of the first one of the pair of signal processor printed circuit boards; and (ii) the bidirectional front end expansion port of a second one of the pair of SAS expander is connected to only the expansion port of the second one of the pair of signal processor printed circuit boards.