SAS and the Enterprise – is Each Ready for the Other?

Author: Mark Peters, Storage Systems Analyst, and Tony Palmer, Lab Engineer
Enterprise Strategy Group

The relative success of new technologies is not a one-way street. Indeed, the history of IT is littered with great developments that never ‘made it’, storage technologies that have had more written about them than on them. 6Gb/s SAS products look great, and full of value, but will the enthusiasm of its promoters be matched by an eagerness to invest from its potential users? With the 6GB/s products rolling out now and over the coming months, there are many Enterprise buyers trying to figure out if, and how far, to jump into SAS. ESG has looked at this from both sides – the technical suitability as well as the adoption logic – and expects that SAS will indeed find success in Enterprise environments.

This article is not intended to repeat in any detail all the well-known attributes of SAS. Yes, it offers a number of benefits compared to traditional parallel SCSI technology including the use of thinner cables, the ability to transfer data over longer distances, providing faster data transfer rates, and the ability to create storage area networks; new and improved capabilities in terms of scalability, performance, capacity, zoning, multiplexing, security and so on, all look great on paper…but is SAS appropriate for and ready for the Enterprise? And is the Enterprise ready for SAS?

Is SAS Ready for the Enterprise?
First and foremost, any technology that is going to be widely adopted into the Enterprise space must be “suitable for purpose”. The technology market is often crowded with nay-sayers; those vendors that do not support a particular technology at a given moment (since they all will once it is a proven success!) are invariably the loudest detractors. So, naturally, there is some discussion around the suitability of SAS. Is it robust enough? Is it the real deal? Entrenched interests and natural inertia can easily combine to create a wariness around new technology, especially when that technology – 6Gb/s SAS being a fine example – appears to combine most all the advantages of prior technologies with few, if any, of the downsides.

The skepticism can take years to be overcome; however, in the current macroeconomic climate, users’ demand for cost-effective, high performance, scalable storage is driving vendors to incorporate SAS as an alternative or even replacement, for traditional Enterprise Fibre Channel drives. For years, large Enterprises have relied on Fibre Channel arrays for their mission critical applications’ data. Traditional Enterprise-class storage systems have provided a bridge between FC connectivity and SATA drives, but have employed Fibre Channel for high performance and “Tier 1” storage. It is ESG’s position that current Enterprise-class SAS drives are on a par with Enterprise Fibre Channel drives, from both a performance and availability perspective and that the market is ripe for tier 1 storage vendors to begin making use of the technology. This “suitability” is not mere assertion – as a couple of real world examples show.

LSI recently used SAS technology to deliver over one million I/Os per second (IOPs) from a single server at the Storage Networking World conference in Orlando in 2009. The demonstration utilized a standard server configuration with 6Gb/s SAS drives directly attached via LSI SAS HBAs and demonstrated the new level of performance of the underlying 6Gb/s SAS technology.

Hitachi Data Systems has led the way among the leading storage system vendors with their Adaptable Modular Storage 2000 family. The current generation of Adaptable Modular Storage systems has a native SAS backend that provides both outstanding price/performance and Enterprise class availability and functionality. ESG Lab tested the AMS family in early 2009, examining capacity and performance scalability, availability as well as advanced storage functionality. Hitachi has published an excellent Storage Performance Council SPC-1 benchmark result of 89,492 SPC-1 IO requests per second at 100% load with an average response time of only 8.98 milliseconds. Figure 1 shows a Response Time/Throughput curve, which visually represents the performance of the system under test as load is increased. A long, flat curve indicates better performance as this denotes that response time stays low as IOPS served increase.


Figure 1: HDS AMS 2500 SPC-1 results


Each member of the Adaptable Modular Storage family, running a 100% SAS back end, posted not only impressive SPC-1 IOPS results and response times but price/performance metrics that stand out from the pack of dual controller, Fibre Channel-based systems. These results, in combination with the Enterprise-class availability and functionality validated by ESG Lab, validate SAS as definitely ready for the Enterprise. ESG expects the functionality and performance of SAS technology to lead to more “SAS inside” enterprise infrastructure in the marketplace. It has a demonstrated capability to provide better price performance than Fibre Channel and ESG expects a growing number of leading Enterprise systems vendors to begin to offer SAS in their architectures.

Is the Enterprise Ready for SAS?
In ESG’s latest annual Enterprise Storage Survey (November 2008), there are some very encouraging signs for the adoption of SAS. The percentage of respondents using SAS in a widespread manner across all tiers and applications was lower for SAS (25%) than for FC (43%). However the number using SAS for Tier 1 or mission critical data and applications only was almost identical for the two (26% and 27% respectively); and once the numbers of those using each technology for Tier 2 and/or planning adoption in 2009 are added in, FC leads SAS by just 87% to 79%. Given that the market for the Enterprise use of SAS is still in its early stages, and given that 6Gb/s SAS is only just starting to roll out, these results provide positive support for the significant adoption and acceptance of SAS. Why should this be? Are users simply enamored of the technical elegance, the combination of capacity and performance perhaps, or is there something more at work?

Earlier this year, ESG conducted an in-depth survey of 492 senior IT professionals from both midmarket (100 to 999 employees) and enterprise-class (1,000 employees or more) organizations in North America and Western Europe concerning their organizations’ IT spending plans and priorities for 2009. Based on the data collected, ESG concluded that cost reduction—and cost avoidance—rule the day for business and IT decision makers. Faced with a global economic recession, corporate cost reduction initiatives were viewed by survey respondents as the most important factor in deciding what, if any, IT investments are to be made in 2009. As seen in Figure 2, users report that cost reduction initiatives will have the highest impact on spending over the next 12-24 months.


Figure 2: Business Initiatives’ Impact on Spending


Put simply, SAS meets a clearly expressed need for the Enterprise user – to help manage costs down. Knowing that it can do that without an impact on performance makes something of a perfect storm for the technology. It means a business fit as well as a technical fit… or, as was posited in the introduction, it means that SAS is ‘suitable for purpose’. As a side note, despite the need to get escalting costs under control wherever possible the survey uncovered another interesting point: 62% of leading-edge consumers in these organizations (defined as users and groups that stay on top of current technology and purchase related products as soon as they’re available) indicated that their IT spending would still increase. This is good news for SAS and those vendors that take advantage of the performance and availability options offered by the technology.

Market success and adoption of any new technology minimally requires two things – a technology must be appropriate for its target market, bringing added value and at least adequate (preferably extended) functionality; simultaneously, the target market must be in need of those benefits (typically in both a business and operational sense) that the new technology can confer. One without the other is simply unnecessary supply or unrequited demand. 6Gb/s SAS appears to meet the qualification, and is poised for significant success in the Enterprise. Each is ready for the other.

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