When iSCSI was finally made to work, I thought it was a great idea and a terrific technological achievement, but I was still sceptical. My attitude was that iSCSI wasn’t sufficiently better than Fibre Channel to stand a chance of displacing it.

The fact is that any company that needs a SAN almost certainly has one already – and it’s probably based on Fibre Channel. As for those organisations that don’t already have a SAN, it is probably because they can do what they need to do with networked storage perfectly well using other technology.

Look at the NAS market, for instance. Several leading NAS vendors, including EMC, NetApp and Adaptec’s Snap Appliance division have added iSCSI capabilities to their filers. Are buyers actually using the iSCSI feature, or is it just a tick-list item when they’re deciding which NAS box to choose? My guess is that it’ll be the latter – at least until more mainstream applications require the block-based access to data that iSCSI and other SANs provide.

Certainly, some firms that didn’t already have a SAN will decide they need one, and will take the iSCSI path; others will even use iSCSI to extend the reach of an existing Fibre Channel-based SAN.

Various forms of IP storage are also beginning to score in storage extension – the SAN over WAN concept that I like to think of as a SWAN, but which IP zealots would probably consider to be an ugly duckling. Whichever nomenclature you prefer, technology to link SANs together over a WAN is finally becoming mainstream. To begin with it was pretty specialist, then the big SAN players came on board – Brocade and Cisco with FCIP offerings, McData buying iFCP pioneer Nishan Systems – and it started to look practical.

Now it’s the turn of the WAN companies. Among the new products at this year’s Storage Networking World Europe, for example, were SAN over Ethernet extenders from Nortel and PacketLight – both companies that are perhaps better known for other forms of WAN cleverness.

It’s interesting to note though that what they’re doing here involves linking Fibre Channel SANs via a long-distance Ethernet service provided by a telco, with no iSCSI in sight. So it still appears that, for the bulk of the market, iSCSI remains an answer in search of a question.

‹ network@bryanbetts.com