Target: ISCSI

It doesn't take a financial genius to understand that the combination of iSCSI transport and SATA (Serial ATA) devices offers the most cost-effective approach to networked storage. To understand how and why, let's refresh our memories about those two technologies.

SATA extends the performance and manageability of what is probably the most common and price-contained disk architecture, Parallel ATA. Check your desktop or laptop, and you will find one or more Parallel ATA devices and controllers, soon to be replaced by new SATA versions that sport a slimmer form factor for cables and connectors. More importantly, they offer point-to-point connectivity between devices and controller ports, and promise performance that will stretch from the current 150MBps to 600MBps within four years.

However, dismissing SATA as just a smarter, faster technology for internal storage on desktops and entry servers would be missing the point. There is a latent market demand for more affordable networked storage that the fast, reliable, and hopelessly more expensive SCSI and Fibre Channel solutions have not been able to meet.

SATA can meet that price demand while compensating for the gap in speed and reliability with numbers -- for instance, adding more spindles to improve the performance or resilience of a RAID configuration.

Nevertheless, SATA is an inbox technology, and you can only push its devices one meter away from the controller. Therefore, to achieve networking ability, SATA needs a carrier able to transfer data blocks outside of its narrow perimeter.

You're probably getting the picture now: By matching iSCSI, the IP-based transport protocol for storage, to SATA devices, you can create storage networks that meet the demands of cost-conscious buyers while maintaining a good level of performance and reliability.

Understandably, vendors in those two areas are sharpening their swords and getting ready to battle for market shares. Serial ATA RAID controllers are an obvious building block for affordable SANs, so you can expect to see new models from vendors such as Promise Technologies and Adaptec hit the street shortly.

A most interesting announcement in this area comes from LSI Logic, which revealed (just before a demo at CeBIT in Germany) its iMegaraid controller, essentially an iSCSI controller with a PCI (or PCI-X) card form factor that hosts two GbE ports and a SATA or Ultra320 SCSI RAID controller.

Expect to see new storage arrays featuring iMegaraid in the first quarter of next year. It could be worth waiting for because LSI Logics estimates that those new networked arrays should bear a price premium of only 5 percent to 8 percent over comparable devices. That sounds good, and it's a view shared by Promise Technologies, which anticipates that the iSCSI-SATA pair will finally cut the cost divide between networked storage and application servers. We'll buy that.

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