STA

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.

Authors: Franco Castaldini, Sr. Product Marketing Manager and
                   Kent Bransford, Sr. Technical Editor
                   Seagate Technology

"Efficiency" is the watchword in today's enterprise as it strives to achieve the optimal blend of performance and cost-effectiveness. To be sure, this can be a delicate balance. Investing in unnecessarily powerful (and costly) solutions is wasteful, yet deploying inexpensive (and underpowered) solutions can seriously degrade system performance and overall productivity. In either case the bottom line ultimately suffers.

Fortunately, the enterprise's heightened focus on efficiency coincides with an unprecedented variety of storage options from which to choose. Spearheaded by Serial Attached SCSI (SAS), a comprehensive range of serial-based solutions now enables savvy IT managers to hit the "sweet spot" of performance and cost-effectiveness by specifying the most appropriate storage device for any given application.

Storage Selection Criteria
To determine which serial disk drive is the most appropriate solution for a specific application, four evaluation criteria can be applied:

• Performance
• Reliability
• Scalability
• Price

Author: Doug Pickford, Director of Product Planning and Strategy,
Hitachi Global Storage Technologies

Hitachi Global Storage Technologies has been working with HP and numerous other companies to help define the Serial Attached SCSI (SAS) standard and deliver products to the marketplace. We recently caught up with HP's Jeff Jenkins to discuss SAS in greater detail, including the benefits he believes it will afford to HP customers.

As vice president of server storage and infrastructure at HP, Jeff's organization is working to ensure that HP's enterprise customers realize maximum performance, reliability and flexibility from their SAS-based systems.