STA

It's nothing new that technology changes rapidly. Enterprise storage is no exception. Keeping data moving at faster speeds and having the ability to properly manage that data has never been more critical to having businesses run smoothly. Applications such as database, commerce and transaction, web serving and streaming use massive amounts of data and storage requirements continue to increase. New technologies need to be integrated into these storage architectures to reduce potential bottlenecks.

6Gb/s SAS Market Update
The market for 6Gb/s SAS is in full swing. Server motherboards are configured with 6Gb/s SAS devices, or RAID controllers. SAS expanders, which allow for incremental scaling of SATA and SAS drive connects, are seeing volume deployments in systems and drive enclosures. By protecting investments in legacy middleware, SAS rapidly transformed the mainstream server market and elevated itself into the leading enterprise storage interconnect. The transition from 3Gb/s SAS to 6Gb/s SAS continued to evolve with the addition of enhanced enterprise-capabilities such as standardized zoning, and expander discovery. The addition of this increased functionality has helped to open new markets and applications, pushing SAS deeper into high-availability storage solutions.

SAS/SATA Compatibility. It's been a goal of the Serial Attached SCSI (SAS) technology since its inception. Originally this meant that a Serial ATA (SATA) drive could be plugged into a SAS port and work well. But that was back in the 3Gb/s SAS days.

SCSI Trade Association October 2009

Q1. What is the Advanced Connectivity Roadmap?

A1. The Advanced Connectivity roadmap is the STA connectivity roadmap to guide the industry through future SAS storage solutions. It specifies the Mini-SAS High Density (HD) (SFF- 8643/8644) connector as the converged connectivity scheme for SAS-based deployments. In addition, it defines SAS Connectivity Management for simplifying cable and connectivity management.

Q2. Name the factors that stimulated provision of the Advanced SAS Connectivity Roadmap.

A2. Factors which drove development and provision of the Advanced SAS Connectivity Roadmap include simplification of cable and connector options and the provision of managed connectivity standards. Additional factors include providing high-density connectivity and the extension of active copper cable to 20m and optical cable to 100m.

Author: Cameron Brett, Manager, Product Marketing, Enterprise and Storage Division, PMC-Sierra
With Contributions by Harry Mason, Director Industry Marketing, LSI Corp.

Not standing still, 6Gb/s continues to innovate with the SAS Advanced Connectivity Roadmap. The industry is trending toward large-scale SAS deployments with thousands of drives, multiple levels of SAS expanders, centralized SAS switches (all incorporating fail-over clustering), server virtualization and bladed processor complexes. This expansion is beginning to tax the basic SAS cabling and connector constructs that have been prevalent over the first two SAS generations.

The market is constantly demanding much more from the SAS interconnect to service increasingly more complex storage systems. The need to manage these large topologies becomes critical as does the greater need for substantially longer cabling distances.

Author: Chris Cicchetti, Marketing Director, SAS/SATA Analyzers and Testers,
Finisar

The new SAS-2 and SATA Gen-3 system protocols bring 6Gb/s link speeds to a wide range of applications, including storage units, disk drives, optical and tape drives, and protocol host bus adapters (HBAs). Carrying such high-signal signals several meters over copper cables, however, tests the limits of signaling technology, making signal integrity a significantly more important design concern for equipment designers and network engineers than it was at 3Gb/s. For example, a test setup that was already at the performance edge for 3Gb/s will cause undesirable and misleading failures at 6Gb/s as tolerances drop to the point where test equipment can adversely affect signal integrity. Apart from strictly adhering to each standard's specifications, the key behind successful SAS/SATA product development and network debugging will be an understanding of the tighter tolerances at 6Gb/s and the steps that developers can take to minimize the impact of test equipment on a device-under-test (DUT).

Author: Cameron T Brett, Manager, Product Marketing
Enterprise and Storage Division,
PMC-Sierra

Serial Attached SCSI (SAS) is now a mainstream technology for enterprise servers and storage. Evolving from parallel SCSI to a serial technology, SAS is much more capable than its parallel predecessor. SAS provides a roadmap to faster speeds and can create, and be managed as a fabric with the use of controllers, expanders and muxes. The standard today is 3Gb/s (300MB/s) across a SAS link. 6Gb/s SAS is coming and PMC-Sierra, an established storage technology provider of SAS, SATA and Fibre Channel solutions, is leading the way.

Author: Susan Bobholz, Intel Storage Group Ecosystem Enablement Manager
and member of the STA Board of Directors

The first generation of Serial Attached SCSI (SAS) products represents a major leap forward in storage technology. SAS drives have a full-duplex throughput of 3.0 Gb/s and are capable of providing a competitive advantage to enterprises that require fast access to data. While today's servers also have 3.0 Gb/s bandwidth, servers soon will be capable of communicating with storage at 6.0 Gb/s. On the other hand, the availability of 6.0 Gb/s SAS devices is expected to lag behind that of 6.0 Gb/s servers. In order to bridge the anticipated gap, the storage industry is looking for ways to take advantage of faster servers by aggregating bandwidth to communicate with multiple storage drives, e.g., enabling a 6.0 Gb/s server to communicate with two 3.0 Gb/s or four 1.5 Gb/s storage drives simultaneously. Bandwidth aggregation would enable businesses to take advantage of faster servers while still protecting their investments in current storage technology. Delivering this capability however, would have both technical and economic implications that must be considered.