It may have failed as a way of extending an existing SAN to more servers, and hasn't been picked up by large enterprises in anything like the numbers forecast by over-eager industry analysts, but iSCSI is still doing nicely. 

So argues Larry Cormier - and well he might, as he's VP of marketing for LeftHand Networks, perhaps the top iSCSI-only storage supplier, and certainly the only one named after a brewery

LeftHand - which just launched the eighth generation of its SAN/iQ software for building iSCSI storage servers - is certainly not alone in thinking iSCSI still has a bright future. As Cormier points out, all the major storage vendors have also piled into iSCSI - indeed, close competitor EqualLogic was snapped up by Dell not that long ago. 

What's finally kicked it into motion was two things, he says. First, Microsoft made an iSCSI initiator a standard Windows feature, so any Windows server could now join a SAN pretty much for free.

And second was the growth of server virtualisation. With multiple VMs running on one physical machine, you end up with an awful lot more running in one tin box. 

In a way, it's a throwback to the days when it was the norm for a whole bunch of applications to share a single minicomputer or mainframe. In between then and now, we tried to simplify things by giving each application its own cheap server, but that ramped up the overall power consumption and moved the complexity elsewhere in the overall structure.

Cormier's contention - borne out in part by the history of SAN and NAS - is that the block-based SAN approach works much better for multiprocessing servers than does file-based NAS.

Block versus file

Going beyond that, he argues that iSCSI block storage works better for virtualised loads than Fibre Channel block storage because the iSCSI interface is itself virtualised, so can cope better with having multiple servers on one host adapter. Sure you could use the new virtualising Fibre Channel adapters, he says, but they're a more complex solution.

"For a long time, we were trying to persuade people that iSCSI could be as reliable as Fibre Channel," he adds. "But now iSCSI has become the de facto storage for new virtual servers - 80 percent of server virtualisation projects involve a new storage purchase, and 60 percent of that is iSCSI." 

What's unusual about LeftHand's is that while NAS suppliers have hastened to add iSCSI capabilities, it has remained iSCSI-only. However, Cormier says the company is officially protocol-agnostic, and is looking with interest at Fibre Channel over Ethernet (FCoE). Like iSCSI, this maps SAN data onto a converged network - but it does it much more efficiently. 

He says FCoE could yet succeed where iSCSI failed, in opening up the high-end data centre to IP-based storage. The snag, he adds, it that it requires a loss-less version of Ethernet, which is still under development. 
 
For the moment, he says LeftHand will focus on using iSCSI to spread the message that SANs don't have to be expensive - its average European sale is around £25,000 - and if they're IP-based, they don't have to be 'different' either.

"80 percent of our sales are still first-time SAN buyers," he notes. "People aren't going to pull out Fibre Channel infrastructures - but people building new data centres are putting in 10Gig Ethernet. And while Fibre Channel tops out at 8Gig today, the Ethernet folks are talking about 20Gig and 40Gig."