As a cheaper alternative to Fibre Channel for building SANs, iSCSI is expected to appeal most strongly to SMBs or low end applications. But until now IBM Corp has been the only tier one vendor of a low-end or even midrange block level iSCSI array. EMC has now eclipsed IBM’s iSCSI effort with the breadth of its Clariion support for the protocol.

Other large vendors such as Network Appliance Inc, Hewlett-Packard Co, or EMC have only been selling high end arrays supporting iSCSI, or slower performing implementations of iSCSI on NAS filelevel devices.

EMC entry into the game makes HP the most conspicuous player standing on this NAS-based sideline, because of its huge share of SAN storage sales. Pre-merger, HP like IBM was an early iSCSI enthusiast. Last week it said it plans additional iSCSI capabilities this year.

iSCSI is still however much more talk than sales. The currently tiny iSCSI market accounted for less than 1% of the total $3.4bn market for all types of external disk arrays, according to IDC’s estimates for the third quarter last year. IDC told ComputerWire that it expects around 190% growth in iSCSI revenue this year.

EMC added iSCSI support to its flagship Symmetrix array in 2003, and to its NAS boxes last year. But it said that those were principally market testers. The Clariion iSCSI support not only fills out EMC’s entire hardware portfolio, but represents the company’s major assault on the market.

Generally we expect the iSCSI market to emerge among SMBs especially those served by VARS and distributors, said Tom Joyce, vice president of storage platforms for EMC.

This is the same target that IBM aimed at last year when it launched its iSCSI-only DS300 array, which lists at around $4,600 with 2TB of disk. IBM will not say how many DS300s it has sold.

The existing noniSCSI Clariion is a big seller for EMC and its volume reselling partner Dell Corp. Last year EMC launched a low cost AX-100 Clariion aimed squarely at small customers served by the channel, listing at around $6,000 with 0.5TB of disk. The new iSCSI Clariions will carry sell for the same prices as existing Clariions, and will range up to the CX500, which lists at just over $68,000 for a base configuration.

Currently the clear leader in the iSCSI market is NetApp, which launched iSCSI support two years ago. NetApp accounted for over 50% of all iSCSI array sales in 2004, according to IDC. iSCSI and NAS both run over Ethernet and so are natural partners, and NetApp has been working to expand from NAS into the SAN or block level market.

But NetApp’s devices combine iSCSI with NAS or file level support. According to Evaluator Group analyst Randy Kerns, this means that they absolutely do not offer the same performance as block level-only iSCSI devices, because the NetApp boxes involve blockfileblock conversions.

This [EMC launch] is about expanding the iSCSI market size, into applications where blockfileblock performance will not be the answer for every customer, he said. EMC is betting on every horse now with iSCSI, Fibre Channel, and combined NAS and iSCSI arrays, he added.

Also, NetApp’s filers support iSCSI via software only, while EMC’s Clariions include a TOE processor at each port.

Unlike EMC and IBM, NetApp sees a market for iSCSI equally split among large and small businesses, and says its iSCSI revenue has been divided about evenly between the two. It says its larger customers are using iSCSI to connect Windows servers into data centers or existing Fibre Channel SANs. These are servers that would not justify the cost of a higher performance Fibre Channel link.

EMC and Kerns repeated the consensus opinion that iSCSI will not replace heavily entrenched Fibre Channel technology, not in the foreseeable future.

Kerns said it may never do. Not necessarily, not in enterprise data centers that want the determinism and performance of Fibre Channel. Whether iSCSI can ever offer those qualities is not yet clear, he said. Probably not in the form it is today. It might be if we get RDMA into 10Gbit Ethernet, but we don’t know if RDMA is going to be a part of the 10G standard, he said.

The Remote Direct Memory Access standard was completed last year by a consortium that includes HP, EMC, IBM, Intel, NetApp and Adaptec. According to the consortium, RDMA is similar to InfiniBand, and will improve the performance of IP links.

Last year EMC said there was no deal for iSCSI until SAN management software was updated to embrace the protocol. Last week it said it had done this for its SAN tools, including Navisphere, PowerPath, and SnapView.

Shipment of the original noniSCSI version of the AX100 was delayed after its official launch last year by production problems. Last week EMC said the iSCSI version is already shipping to Dell and to EMC’s other resellers.