Slowly but Surely, SAS Is Forging Ahead

Serial Attached SCSI is gaining vendor support and is expected to become more prevalent in the next year, particularly at the low end of the market.

Many storage vendors have a great deal riding on the success of Serial Attached SCSI, with most incorporating the burgeoning technology into current and future product announcements and enhancements.

Touted as the replacement for parallel SCSI, SAS provides many benefits for the relatively small but growing number of organizations intent on adopting it: higher performance, faster transfer rates, better scalability and less cabling.

Experts believe that SAS eventually will become the primary technology used in drives for servers and workstations, replacing parallel SCSI.

"The same way ATA drives turned into SATA drives inside servers and workstations, SCSI drives will turn into SAS drives," said Brian Garrett, an analyst with Enterprise Strategy Group, of Milford, Mass.

Already, drive vendors such as Hitachi Data Systems, Maxtor Corp., Fujitsu Computer Products of America Inc. and Seagate Technology LLC are augmenting their SCSI-based drives with SAS drives, and server vendors like Hewlett-Packard Co. and IBM Corp. are offering servers based on SAS technology. Other vendors like Dell and Sun Microsystems are sure to follow. And, of course, chip vendors also are in the SAS game, the largest being Adaptec Inc. LSI Logic Corp. and Broadcom Corp.

Although it may seem like SAS has been a long time coming, the technology has been on a reasonably brisk course for years, said Greg Schulz, a senior analyst at Evaluator Group of Greenwood Village, Colo.

"When the component suppliers start shipping doesnt mean thats when it ends up in the users IT environment," he said. "Its only in the past four or five months that its actually been shipping as a consumer product, but its gaining ground. It has a very bright future, but it will take some time."

Now that SAS drives are gaining a foothold in the server world, IT administrators must decide whether to move to the technology for their organizations servers and workstations, or whether to use SATA (Serial ATA) drives—generally a cheaper option, at least in the short term.

For the time being, SATA is still an attractive option for laptops, desktops and low-end servers, as well as inside of external storage subsystems, because of their large capacity and lower price point, Garrett said.

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Realizing the pull of each technology, some vendors have introduced a SAS/SATA combination—something Schulz said makes a lot of sense.

"As vendors start to come out with new arrays, they will be able to truly mix different drives into those enclosures and have a common shell they can use for either SAS or SATA," he said.

Schulz expects the SAS/SATA combination drives to be more heavily adopted at the lower end of the market, where their lower cost and smaller impact will make the greatest impact. "They could use SAS for high performance, high availability and robust online primary storage, with SATA for their secondary or nearline storage," he said.

By next year, SAS also will become more prevalent on blade servers and will begin appearing in RAID arrays and perhaps even enterprise arrays, Schulz said. Prices also should decrease as volume increases, he said.

By this time next year, Garrett expects to see SAS become standard, especially on high-end servers. A year from now will also be the crossover point where SAS will overtake SCSI shipments and may even be the time when SCSI will no longer be an option on high-end servers, he said.

"My guess as to when volume SAS really takes off and buries SCSI is late 2006 or early 2007," he said.

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