Storage World: Lots of serial on the shelves

StorageTek's IntelliStore puts SATA disks and tape drives in a single unit.

The Pillar Axiom is a SATA-based network-attached storage system.

Serial-attached storage is the dominant theme, although serial-attached SCSI still has a ways to go

At last month's Storage World Conference near Los Angeles, the exhibit floor was rife with serial-attached storage solutions. Chief among them: serial ATA products.

Most motherboard makers offer SATA connections and, starting early next year, will introduce SATA-only boards. In the past few years, storage vendors have also rolled out SATA-based arrays for low-cost storage, finding new niches in the cost-versus-performance tradeoff of storage systems.

Storage vendor start-up Pillar Data Systems of San Jose, Calif., recently introduced its Pillar Axiom, a SATA-based network-attached storage unit that costs about a fourth of what other NAS system cost. StorageTek Corp. of Louisville, Colo., released an archiving appliance called IntelliStore that uses both tape and SATA disk storage. The SATA disks provide space for the material accessed most, while the software offloads the least accessed material to tape. (Last month Sun Microsystems Inc. agreed to buy StorageTek.)

On the pricier end of the continuum, EMC Corp. of Hopkinton, Mass. released a Clariion storage array that contained Fibre Channel-connected disks and SATA disks using the same controller. The SATA disks provide cheap, slower storage that could work as a backup for the speedier Fibre Channel disks. 'Even a small division with relatively meager capacity requirements can tier their storage,' said Ken Steinhardt, director of technology analysis for EMC. 'The key is to optimize whatever is appropriate for the application.'

Serial-attached SCSI has been slower to gain a foothold in the market, for a variety of reasons. Industry experts at Storage World speculated that big storage vendors were slow to adopt SAS because it could pose a threat to the lower end of the expensive Fibre-Channel storage market. Future iterations of SAS disks could run almost as fast as Fibre Channel disks. They would also come with traditional Fibre Channel features, such as better scalability and dual-ported failover capabilities.
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'The people who are already interested in SAN see less reason to adopt SAS,' said Rob Peglar, a member of the Storage Networking Industry Association and vice president of technology marketing for SAN manufacturer Xiotech Corp. of Eden Prairie, Minn.

EMC, for instance, has remained on the fence on SAS. 'It's an emerging technology,' Steinhardt said. Thus far, EMC hasn't an- nounced any SAS products.

In fact, very little SAS equipment is actually available yet. Only a handful of manufacturers are now offering SAS disks, notably Fujitsu Ltd. of Tokyo and Seagate Technology of Scotts Valley, Calif. Integrated circuit manufacturer LSI Logic Corp. of Milpitas, Calif., has started producing a series of SAS port expander chips, but manufacturers probably won't be adding them to their motherboards and storage array components until early 2006, said Martin Czekalski, vice president of the SCSI Trade Association.

Still, agencies looking for a smaller SAN may want to wait and see if the first batch of SAS could meet their needs. At Storage World, Fujitsu showed off an early serial-attached SCSI system. Don Jeanette, senior manager of product marketing for the company, demonstrated a prototype SAS-based system with 16 small-form factor (2.5-inch) 73.5 gigabyte drives hooked up to a server through a single expander. A performance measurement program on the server showed a combined throughput of around one gigabyte per second. A standard SCSI setup of similar capacity would only offer half that throughput, according to the company.

Whatever the present situation, industry observers predict that SAS will be widely adopted in the market, easily replacing the still widely entrenched SCSI and maybe even offering a lower-priced alternative to SAN Fibre Channel disks.

'We think that that over time SAS will start to replace Fibre Channel at the drive level,' said Ron Engelbrecht of Engenio Information Technologies Inc. SAS drives would have a price advantage and greater compatibility than those drives with the Fibre Channel interface. Engelbrecht said the Fibre Channel interface could still be used to connect the storage array to the network, though.

About the Author

Joab Jackson is the senior technology editor for Government Computer News.

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