| Next-generation technologies
to boost platter density
Current giant magneto-resistive (GMR) head technology and longitudinal recording techniques are approaching physical limits. Bits are packed so tightly on the platter that the magnetic charge used to denote a one or zero can flip spontaneously if things are compacted much more.
Vendors are turning to some new technologies to overcome this hurdle. One approach--demonstrated late last year by Maxtor Corp.--embeds magnetic elements vertically into the disk surface, allowing bits to be more tightly packed on the platter. Known as perpendicular recording, Maxtor's demonstration of the technology produced a per platter density of 175GB, nearly double that of any product currently on the market.
Another approach, called heat-assisted recording, takes a page from optical drive technology. This process employs media that will only switch magnetic orientation when heated to a specific temperature. The approach eliminates the danger of spontaneous field change, but at a cost in complexity because a laser must heat the media. While promising, both techniques require significant investment and a changeover in drive manufacturing and supply. In short, it will be years before either approach will drive up disk densities.
Form over function
Even as drive makers jigger the interface, they are hard at work shrinking the drive enclosures. Seagate recently launched its Savvio line of small form factor enterprise-class drives based on a 2.5-inch package. The size reduction from current 3.5-inch designs offers a host of benefits, including a smaller footprint, lower power consumption and heat output and reduced acoustic and vibration levels. Later this year, expect to see 10K rpms 2.5-inch drives. The wait for 15K rpms high-performance 2.5-inch drives will extend at least into 2006 and possibly later.
Brian Kraus, senior global marketing manager at Seagate, says the smaller drives allow 1U servers to hold a complete, four-disk RAID 5 array, with redundant disks dedicated to data and to the operating system. By contrast, 3.5-inch drives require a 3U server design to provide the same capability.
Both Maxtor and Seagate have announced 2.5-inch form factor drives, with production models expected to reach the market in the second half of 2004. Initial designs will be relegated to DAS, while array makers such as EMC and HDS mull the significant costs of reengineering cabinets and plumbing for the new drives.
Joe DeRosa, senior director of enterprise storage marketing for Maxtor, expects that small form factor drives will make headway in the market in 2005, with measurable volumes occurring in 2006. Once the small form factor tide turns, the switchover should happen fast. Gartner Inc. projects that that by 2007, 2.5-inch form factor drives will lead enterprise sales.
The smaller drives could enable new breeds of disk-based storage. ESG's Kenniston sees a future where companies can buy sealed 2U boxes with multiple terabytes of storage, which can be plugged into a SATA or other connections. The result is truly commoditized disk storage that can serve anything short of critical applications.
For example, SpectraLogic sells a 12-disk cartridge that plugs directly into the company's Spectra T950 tape library. A Spectra RXT cartridge can hold up to 1TB of RAID-protected data, for fast, virtual tape library functionality. It's an approach that could gain momentum as enterprise-ready, 2.5-inch form factor drives hit the market at reasonable price points.
Recommendation: Small form factor drives are an exciting development, but the early premium charged for these products will hinder proliferation. Until prices for 2.5-inch models drop--probably in 2006--most shops will find themselves well served by the traditional 3.5-inch form factor offerings.
The increased number of drive technologies targeting the middle of the enterprise drive market reflects a significant crossover of product categories that began in 2003. The arrival of the first so-called "Enterprise ATA" drives from Maxtor and Western Digital has kicked off a mingling of drive types, and the trend shows no signs of abating through the end of 2005.
The second-half of 2004 should see significant sales of enterprise ATA drives, with large volumes going into nearline and emulated tape storage solutions. These ATA drives typically offer mean time between failure (MTBF) numbers close to one million hours--significantly higher than desktop-rated ATA drives.
Driving the trend are continuing improvements in reliability from ATA-based products--improvements that could shake up vendor product lines, says ESG's Kenniston. "Over the next 12 to 18 months, the quality of ATA will get significantly better and it will be driving increased sales," says Kenniston, adding that "vendors are often more scared about positioning--why is the 2.5 times the cost for Fibre Channel worth it?"
It's a good question, and one that Hewlett-Packard Co. recently sought to answer when it announced a new class of Fibre Channel-based drives called Fibre-Attached Technology Adapted (FATA). FATA drives offer native Fibre Channel protocol operation--enabling enterprise customers to standardize on a single storage architecture, while delivering significantly reduced costs. Yankee Group's Balaouras expects that FATA-based drives could be priced about 30% below those of similar capacity Fibre Channel drives and will offer capacity up to 250GB with a dual-port, 2GB/s, Fibre Channel interface.
Recommendation: If you're standardized on Fibre Channel now, FATA can help keep the environment simple while offering good reliability and performance. Mixed environments can benefit from the improving reliability of enterprise ATA drives.
This was first published in June 2004