Author: Ahmad Zamer, Manager, Storage Industry Initiatives, Intel Corporation
Pacing SAS Adoption Progress
The apparent eagerness for higher performance Serial Attached SCSI (SAS) calls for a pause to look at the allocation of industry synergies as we push for SAS adoption. There is no doubt that the future of SAS depends on its successful adoption over the next few years and all effort should be focused on driving the highest possible adoption rates. In addition to that, all proposed new enhancements should be embraced proportionally to their ability to facilitate SAS adoption. Driving successful SAS adoption takes precedence over other considerations, for without it; future SAS generations may not evolve. At this time, an updated version of SAS (1.1) is on its way to becoming an industry standard. Even before that version is complete, discussions are starting on the next generation, a faster version of the technology known as SAS-2. The expectation is that SAS will last a long time, so there is no urgency to rush headlong into the next generation of SAS technology.
It is unlikely that there will be major shifts in global economic conditions and the IT environments that have existed for the past three years. Without major improvements, adoption of new technologies tends to happen at a slow pace. The good news is that SAS has a lot in its favor and that situation alone will facilitate its adoption. To start with, SAS is the natural next step for SCSI, the most popular enterprise-level storage interface. Second, SAS seems poised to expand into areas not yet occupied by competing enterprise storage technologies. Third, SAS vendors are addressing consumers’ genuine needs for next generation storage.
Building on the SCSI Base
Despite the remarkable rise of Fibre Channel (FC), SCSI continues to occupy a majority share of installed storage systems in enterprises worldwide. FC has made its gains in networked storage that benefited from its performance and availability features. On the other hand, Direct Attached Storage (DAS) installations remain dominated by SCSI. SAS is the natural choice for DAS as the SCSI replacement due to its nature as a serial SCSI interface that fits into SCSI environments without requiring changes or causing any disruption. In networked storage, SAS point-to-point architecture offers users the bandwidth they desire. Dual-port SAS drives complement SAS features for networked storage, making SAS as highly available as users may desire. Like SCSI in networked environments, SAS will likely reside outside the fabric, leaving that for networking technologies. The SCSI nature of SAS makes it a natural choice for DAS, while its enterprise resilience makes it a strong contender in networked storage environments.
Power, Capacity, and Price
Progress brings with it remarkable changes to users’ priorities and attitudes towards technology. Not long ago, it was hard to talk to any customer without having to address system performance and speeds. Today, while performance remains significant, users have turned their attention to more pressing issues such as space, heat dissipation, and power consumption (since power consumption and heat dissipation are closely related, the terms will be used interchangeably in this article). Space utilization, or system density, is not as much of a problem to large data centers as it was just a few years back, thanks largely to blade or rack-mount 1U servers. On the other hand, power consumption and heat remain top priorities. SAS will be a welcome relief to enterprise users due to the attention paid to the issue by the SAS community. The new 2.5″ drives will consume about half the power of standard 3.5″ drives and dissipate proportionately less heat. The interesting thing to look at is the ratio of power and capacity-or even price, power and capacity. Some SAS hard drive vendors are paying special attention to managing the power consumption of 3.5″ drives to favorably balance the power-capacity-price ratios. Having attractive power-capacity-price ratios for 3.5″ drives give users another great option to consider alongside low-power and high-density 2.5″ drives. Giving users flexibility in selecting storage solutions that meet their financial, power, or space budgets is a powerful incentive to buy SAS.
SAS Ecosystem
In order for new technologies to flourish, they require an ecosystem that nurtures and supports them. The past few months have witnessed the emergence of a budding SAS ecosystem that has the potential to support stable SAS deployment and expansion. Today, users can chose components for SAS solutions from multiple sources supplying hard drives, SAS controllers, expanders, and SAS storage arrays. Today, SAS components are available from several vendors and in many flavors and configurations. Though it continues to strengthen, the SAS ecosystem is still in its start-up phase and customer adoption remains hesitant. Users are gradually building their confidence in SAS and are slowly expanding their deployments. Considering the state of user adoption and that of the SAS ecosystem, the sensible thing to do is give the ecosystem the time it needs to become more robust. It is also necessary to give users time to deploy SAS more widely and to learn from their experience in shaping future SAS versions.
Summary
SAS is the natural next step for SCSI technology and the natural choice for users looking to upgrade their SCSI environments. With its point-to-point topology and dual-port drive design, SAS is ready to play an active role in networked storage. The recent product announcements and availability of SAS products in the marketplace are enabling users to deploy SAS using multiple vendor components. As with other technologies in early stages of development, the SAS ecosystem is still young and will take some time to mature by benefiting from user experience. The sensible thing for the SAS industry to do is to pause for a brief period to learn from customers’ experiences and then integrate those experiences into future SAS versions. Rushing forward too quickly may deprive the ecosystem of properly maturing and may cause customers to pause and wait for the next cycle of SAS products. Balancing the needs of emerging ecosystems and early technology adopters with those of the inevitable advancement of technology is a delicate act that the SAS community must perform successfully to move SAS to the next version with no disruption to its growth.
