STA

Author: John Rydning, Research Director, Hard Disk Drives
IDC

Storage device options continue to broaden for disk storage system OEMs and end users. For enterprise applications, hard-disk drives (HDDs) are now available in several form factors, configured with parallel SCSI, Fibre Channel, Serial ATA (SATA) or Serial Attached SCSI (SAS) interfaces. An increasing number of solid state drives (SSDs) are now also shipping for enterprise applications. DRAM-based SSDs have for many years satisfied the needs of very high performance, latency-sensitive environments, but at a high cost. Now, with the price decline in NAND flash and advances in technology, NAND-based SSDs have a growing opportunity in the datacenter. Similar to HDDs, flash-based SSDs are offered with several interface options.

Today's diversity of storage device options for the datacenter contrasts sharply with the limited selection available just five years ago. Consider the changes that have taken place just with hard disk drives. In 2003, essentially two HDD form factors serviced the large percentage of enterprise datacenter storage demands: 3.5 inch 10,000 rpm and 3.5 inch 15,000 rpm HDDs. Today, in addition to these 3.5 inch enterprise class products, the HDD industry also ships 2.5 inch 10,000 and 15,000 rpm enterprise-class small-form-factor (SFF) drives. Collectively, IDC classifies these drives as performance-optimized HDDs. By 2009, 2.5 inch performance-optimized HDDs will out-ship 3.5 inch products.

Author: Mike Karp, Senior Analyst,
Enterprise Management Associates

"Storage density" is the term that describes how much storage capacity can be packed into a specified amount of space. The actual measurement varies a bit depending on your focus. Disk drive vendors measure bits per square inch, while tape vendors think in terms of bits per linear inch. Data center managers measure things at a more macro level: for them storage density is a measure of terabytes (and increasingly, petabytes) per square foot of floor space.

At least that's the way things were measured up until recently.

Author: Karin Gilles, Corporate Communications,
Hitachi Global Storage Technologies

Data center workloads have increased exponentially in recent years, requiring IT managers to find new ways of scaling their enterprise storage resources so that they are both highly reliable and cost effective. With the introduction of complementary serial interface technologies, IT managers now have the flexibility to deploy either high-performance Serial Attached SCSI (SAS) drives or cost-effective Serial ATA (SATA) drives (or both) in a SAS environment.

This approach to tiered storage allows IT managers to control costs and pair the less frequently used data with lower cost-per-gigabyte hard drives, while freeing high-performance SAS drive resources for mission-critical applications.

Author: David Woolf, Senior Storage Research Engineer and Principle SAS Consortium Engineer,
University of New Hampshire-InterOperability Laboratory (UNH-IOL)

This is an exciting time for Serial Attached SCSI (SAS). Its development curve has been extraordinarily smooth and swift, products are now launching and market entry will accelerate as 2005 goes forward. The last of the dust clouds are dissipating, and it's becoming clearer what role SAS will play in the near- and not-so-near-term data center market.

Greasing the Skids
The rapid SAS market ramp-up owes much to the forethought and careful planning of key engineering players and organizations like the SCSI Trade Association (STA). In fact, SAS' smooth transition from the engineering white board to the marketplace should be taken as a model for successful technology development. This process succeeded for two key reasons: First, SAS didn't reinvent the wheel. Its development incorporated and built upon older, well-established technologies such as SCSI and the trusted XAUI (see definition two paragraphs below) physical layer. Second, interoperability tests were built into the development process from the start. Amazingly, this is not necessarily the rule with new technologies.

Author: Ahmad Zamer
Intel Corporation

On a recent trip to the North East, I had the opportunity to visit the data centers of two corporate customers. The first was an Internet Service Provider (ISP), the second, a mid-size brokerage firm. Both organizations, despite their different businesses, spoke of similar challenges their Information Technology (IT) staffs face. They also spoke of similar needs they wanted to be able to meet using new technologies.

Real-World Data Center
The ISP's manager of data center operations spoke in terms that may not be unfamiliar to technical people who work on industry standard and storage product design. He talked about his needs and challenges in terms of how they relate to floor tiles. He measured the value and utility of every storage and server solution in terms of how much precious real estate they would occupy in his data center. Following a three-hour tour and lecture from the data center director, one finds it hard not to measure everything using the "tile factor."

From the ISP's perspective, the major challenges were the limited power, per tile, they can bring to the data center, and the ever-rising costs of cooling per tile. These are simple metrics that have serious implications for all new computing technologies, especially storage technologies. Pointing to huge boxes scattered across the data center, our guide shouted, "Do you see these huge boxes? These are my storage boxes and I don't seem to ever have enough." So, how can one keep adding big storage boxes to the enterprise infrastructure without negatively impacting the tile factor?