Seagate ST3300657SS Enterprise-Optimized 6Gb/s SAS Rivals Fibre Channel Perfor - Page 1

Technology Paper Enterprise-Optimized 6Gb/s SAS Rivals Fibre Channel Performance and Scalability at Lower Cost Introduction In just a few short years Serial Attached SCSI (SAS) has fundamentally altered the enterprise storage landscape. Building on the rock-solid reliability and robust command set of its parallel SCSI predecessor, SAS raised the storage bar with an unprecedented combination of performance (3-Gb/s transfer rate), scalability (thousands of devices in one domain) and flexibility (compatibility with SATA). In Q3 2005, 3Gb/s SAS systems entered the market and by 2007 were shipping in volume quantities. SAS has supplanted parallel SCSI as the direct-attached SCSI interface of choice throughout the enterprise; indeed, it was one of the fastest interface transitions in market history. This rapid transition relied on the close working relationship between the SCSI Trade Association (STA) and the T10 Committee. The STA focuses on identifying SCSI's marketing requirements and providing the forum to reach a consensus on features and benefits found on the SCSI roadmap, while the role of the T10 Committee is to develop standard specifications to make it possible for those features and benefits to be implemented in commercial products. The T10 Committee developed the new SAS-2 technical specification (SAS protocol and physical interface enhancements for transporting SCSI over serial links at up to 6 Gb/s), and the STA has given the marketing name "6Gb/s SAS" to this new industry standard (see Figure 1).