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Serial ATA (SATA) is fast becoming a standard part of enterprise storage environments. Storage vendors are placing SATA drives in increasing numbers of enterprise storage systems for a variety of different uses. But how far SATA will ultimately penetrate the enterprise storage ecosystem is a question that is open for debate.
Gartner Group has forecast that by the second half of 2005, SATA will be the dominant HDD interface, and that by the end of 2007, it will achieve 100 percent penetration across all notebook and desktop HDD markets.
IDC has also noted the growing presence of SATA in enterprise storage as well.
"Mostly to date, we've seen this through products that have been positioned for 'secondary' storage — for non-mission critical applications or consolidation of backup, disk-to-disk backup, etc.," IDC analyst Brad Nisbet told Enterprise Storage Forum.
"We continue to see this encroachment of ATA evolve, as many disk storage systems vendors are beginning to position products that can mix both Fibre Channel and ATA drives, allowing for flexibility in the tiering of storage based on customer and application needs," Nisbet said. "It is through this flexibility that the lines of primary and secondary storage begin to become blurred, but nonetheless, the advancement of ATA technology in storage systems is clear."
SATA Enables ILM
Hu Yoshida, CTO of Hitachi Data Systems (HDS), does not see SATA as a solution in itself, but rather as part of a multi-tiered storage approach such as information lifecycle management (ILM).
"In the past, the way enterprises used tiered storage was to assign a tier one with high-class enterprise storage," Yoshida said. "The problem is for the life of all that tier one data, it remained on that expensive storage. We know that as that data ages, access requirements will drop off and you could move it to lower-cost storage. Up until now, that movement was too costly, so most people just left it on the highest-cost storage."
HDS added SATA in response to customer demand for cheaper storage, although Yoshida admits that the company wasn't entirely confident about the technology.
"We had reservations about going to SATA because it is less reliable," Yoshida said. "In fact, we put additional functions in our control unit to compensate for that."
A Disruptive Influence
SATA is one of the factors that is also contributing to the continued pricing pressures that storage vendors are facing, with growth in petabytes shipped far outpacing industry revenue growth.
Craig Butler, IBM's disk products marketing manager, disputes the notion that SATA is driving the profitability out of the storage business.
"Let me assure you that the industry trends for lowering prices, 35 percent a year on a per terabyte basis on Fibre Channel, was happening anyway," Butler said. "It's been happening for years."
Jay Krone, director of CLARiiON platforms marketing at EMC, does not see SATA as disruptive technology, except perhaps to tape vendors.
"ATA drives meet the performance requirements of backup but do not meet the needs of other apps, most notably OLTP (online transaction processing) and a big chunk of database apps," Krone said. "We view it as incremental and not disruptive. The advantage of having it implemented is that we have our bets hedged against it being disruptive."
To EMC, multi-tiered Fibre Channel and SATA storage allows for ILM in a box.
"Our customers get it and a lot of people buy ATA that way," Krone said. "They'll buy a Fibre Channel production array and they'll buy a few terabytes of ATA to go on that array to put less active data. As info has less value in real time, it makes sense to put it on media that is more economical."
In Hu Yoshida's view, SATA has caused a major change in the marketplace and has been very disruptive. Yoshida noted that it's difficult to sell a high-end enterprise-class storage product when the user is looking at something that is one third or one quarter of the cost.
"How do you compete as a high-end storage vendor against a very low-cost storage that may be good enough in many cases?" Yoshida asked. "The solution is to change the playing field."
The HDS approach has been to separate the control unit from the disk array. The item that has value is now separated from the disk arrays that have become commodities.
"We can build our disk arrays to compete," Yoshida said.
SAS Effect Has Yet To Be Felt
SATA adoption is being fueled by an almost insatiable customer demand for storage. According to IBM's Butler, as serial attached SCSI (SAS) products begin to appear on the market and compete against Fibre Channel, it too will boost adoption of SATA in the enterprise, since SAS backplanes also support SATA drives.
"The reason is that the SAS and SATA interface specification have been held close together by the development communities," Butler said. "We'll be able to put up systems where you can mix and match SATA drives much more easily than you can mix and match Fibre Channel and SATA."
With SAS products set to appear in the second half of the year — and products equipped with many of the SATA II features also hitting the market — SATA's growth may just be getting started.
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