Author: Tonya Comer, Product Marketing Manager
Industry Standard Servers, HP
Serial Attached SCSI (SAS) is a point-to-point disk interface that builds on the functionality of SCSI for the enterprise. Borrowing reliability and performance enhancements from Fibre Channel, SAS supports dual-port and full-duplex communication between servers and disk drives. SAS extends reliability and bandwidth opportunities by using expanders to create wide ports, which are multi-path connections between the server and storage solutions. SAS also improves manageability of the storage solution by providing the Serial Management Protocol (SMP) to monitor connections between individual devices and identify points of failure or reduced performance.
The first generation of SAS achieves bandwidth as high as 300 MB/s per link and operates in full-duplex mode, in which data, commands, or status information flow bi-directionally. The SAS interface allows for combining multiple links to create 1x, 2x, 3x, or 4x connections for scalable bandwidth. In contrast, Ultra320 SCSI has a half-duplex bandwidth of 320 MB/s per channel.