SAS expansion topology for RAID data storage system

摘要

A data storage system includes a first chassis that has a pair of storage processors, a pair of SAS expanders having a bidirectional front end port and a plurality of bidirectional backend ports, and an expansion port, a pair of SAS controller each one being coupled between a corresponding one of the pair of processors and a corresponding one of the pair of the expanders, and a first plurality of multiplexers. Each one of the multiplexers has a pair of bidirectional front end ports and a pair of bidirectional back end ports. 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, 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. The first chassis also has 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. The systems also has a second chassis that has a pair of SAS expanders. Each one of the pair of SAS expanders has a bidirectional front end expansion port and a bidirectional backend expansion port. The second chassis also has a second plurality of multiplexers. Each one of the second plurality of multiplexers has a pair of bidirectional front end ports and a pair of bidirectional back end ports. 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. 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. The second chassis also has 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. 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. 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.