Author: Rachelle Trent, SAS Product Manager,
As enterprise storage requirements rapidly increase, expanding data throughput and providing scalable storage capacity is crucial. The goal of Serial Attached SCSI (SAS) was to overcome the scalability and reliability limitations of parallel SCSI and to significantly improve the ability to add hard disk drives to a system. To overcome the scalability limitation, SAS uses devices such as expanders and multiplexers (muxes).
Expanders for scalability
SAS expanders provide scalability and enable fault tolerant systems by providing multiple connections between hard disk drives and initiator devices. These redundant links between hosts and drives maintain a connection in case of a system failure. In addition, SAS expanders provide high throughput and facilitate the compatibility between SAS hosts and Serial ATA (SATA) disk drives. Expanders simplify the configuration of large external storage arrays and can be cascaded with minimal latency while preserving bandwidth for increased workloads.