SFF SAS: Everything is in Place to Realize Benefits

Author: Don Jeanette, Senior Manager, Product Marketing
Fujitsu Computer Products of America

Adoption is Happening:
For nearly two years, a variety of Serial Attached SCSI (SAS) products has been available in the marketplace. In 2006, the hard disk drive (HDD) industry anticipates shipping as many as 2.5M to 3M enterprise products with SAS as the preferred interface. This will represent approximately ten percent of the overall enterprise hard disk drives shipped for the year. In parallel, it is evident that small form factor (SFF) SAS hard disk drives are continuing to gain momentum.

Hardware Options are Available and Proven:
A host of companies are selling SAS products today, helping to drive its integration in the industry. Everything from controller cards, servers, storage systems and cables are now available for purchase from multiple vendors. The SCSI Trade Association has done a considerable amount of work to communicate the availability of these products, as well as to promote the technology’s adoption. Additionally, IT managers can feel confident that these products have been tested for interoperability at multiple plugfests held at the University of New Hampshire over the past several years. These plugfests include participation from organizations representing all of the hardware components needed to build SAS-based systems. Finally, Fujitsu has also taken on the SAS initiative with the launch of the Fujitsu FACT Lab™ (Firmware and Compatibility Testing).

Advantages of Smaller Hard Disk Drives:
The necessity of moving to smaller form factor HDDs continues to push the marketplace, and the enterprise segment is no exception. SFF (2.5″) SAS hard disk drives offer numerous benefits over the traditional 3.5″ form factor hard disk drives. Power consumption and floor space are two factors that are consistently a challenge for IT managers. Because 2.5″ HDDs feature 60 percent less power consumption vs. 3.5″ models (4.5W vs. 11.25W), these units are more appealing for use in critical data systems.

With more and more SFF SAS-based systems being deployed, companies are also discovering that utilization of the 2.5″ models has led to a reduction in space requirements. Finding enough actual floor space for data centers has grown more difficult with each passing year. However, with systems designed around HDDs that take up less space than 3.5″-based solutions (by a factor of almost four as it relates to the hard disk drive), IT managers are able to build data centers that take up less floor space, while at the same time lowering their power bill and increasing the system’s reliability.

Transitioning to a smaller form factor product does not mean users must sacrifice on reliability. In fact, reliability has improved with the latest generation of SAS hard disk drives to 1.4M hours mean-time-between-failure (MTBF). Additionally, lower power consumption means less heat is generated within the system. This can translate to fewer cooling requirements (less money spent on fans and cooling systems) being needed overall.

The benefit of scalability with SAS has been discussed at length throughout the industry. Taking this a step further, configuring a system with SFF SAS permits this scalability without compromising on space. Users can pack more SFF SAS drives per U rack-mount vs. 3.5″ hard disk drives. This translates into a greater number of spindles operating in a smaller amount of space, resulting in both increased performance and scalability.

Additional perks to transitioning to the 2.5″ hard disk drives are often overlooked. Some of these factors include improved operating and non-operating shock, as well as reduced acoustic noise.

There are a great number of advantages to using 2.5″ SAS hard disk drives over traditional 3.5″ enterprise products. A brief summary of the benefits are listed in table 1.


Figure 1: Benefits of 2.5″ SAS Hard Disk Drives over 3.5″


Fujitsu has been shipping its 2nd generation SFF SAS product, the MAY2073RC series, for almost two years. With capacities of 36GB and 73GB, the MAY2073RC series features 1.4M hours MTBF and power consumption at 40 percent of the average 3.5″ enterprise hard disk drive. The high-performance Fujitsu SAS HDD effectively addresses the concerns that are being voiced by IT managers, and its robust features are ideal for what the market is requiring today.

In Conclusion:
The industry has adopted SAS as the new technology in the enterprise segment. When integrating this technology using SFF SAS hard disk drives, users will experience a host of benefits including lower power consumption, reduction in space requirements, reliability and scalability. Plenty of resources are available to anyone who has questions or concerns on how to acquire, build and deploy this technology.


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