ONStor's latest storage product will not only save money but expand storage capacity beyond all its competitors. It is the last NAS you'll ever need, claims the company.

The ONStor Bobcat 2200 Series NAS Gateway supports a massive 4PB of storage, split into 400 separate file systems of up to 100TB each. NetApps's gFiler only scales to 6TB, according to Jon Toor, ONStor VP of marketing.

Bobcat consists of a 1U-high rack servers runnning Linux. These are clustered pairs for high availability, and serve files, stored on multi-vendor storage arrays, to Windows, Unix and Linux clients. "This n-way clustering is unique," said Toor.

Performance scales by adding more Bobcat servers. They are virtualised, in an analogous way to VMware, and users can be assigned to different physical Bobcat servers as needs grow or as one Bobcat server fails and the system automatically moves its workload to another.

An evaluation report on the gateway by the Enterprise Strategy Group (ESG) states: "The ONStor Bobcat can essentially create virtual NAS servers from a single Bobcat cluster. This allows system administrators to consolidate physical NAS systems but still provide virtual NAS systems to different departments and users creating a NAS utility environment."

Workloads can also be load-balanced across the cluster nodes. NetApp announced SnapMover load balancing software for its gFiler range in December, 2003.

Toor says that individual NAS products, like ones from EMC and NetApp, require customers to buy additional products and migrate data and users to them when capacity limits are reached. With Bobcat, customers need only have a single NAS product which grows as they grow, supporting up to 20,000 users if need be. They don't end up with dozens of separate NAS boxes each needing separate management, the company argues.

Hamish Macarthur, founder of Macarthur Stroud International told Techworld: "ONStor has certainly taken virtual servers one stage further. With ONStor you can grow servers without bringing the system down. With NetApp in some cases there are one or two issues wth doing that."

Data is protected through snapshot and disk-to-disk replication facilities with tape backup as a further option. The Fibre Channel-attached drive arrays holding the file data are virtualised into a single logical pool of NAS storage. Extra capacity can be added when needed and becomes part of the pool. Fibre channel-attached disks from an existing SAN can be added to this pool.

Robert Stevenson, a technology strategist for the Nielsen Media's company's Media Technology Services Division, said: "We concluded that ONStor had an exceptionally elegant solution. Overall, we found it to be a very solid NAS product at a reasonable cost." "[Head-to-head comparisons] proved ONStor's price/performance/reliability and heterogeneous storage platform support to be superior to all other contenders."

Macarthur provided caveats concerning how you actually achieve such multi-vendor virtualisation: "Having this approved by all the array suppliers is a challenge. A key thing is how do you synchronise RAID levels and recovery structures as you move from, for example, Hitachi to EMC arrays."

Several other companies are supplying or developing virtual NAS technology, including Rainfinity, Acopia Networks, NeoPath and NuVie. Some of these have a single global namespace instead of separate file systems.

ONStor believes that NAS consolidation will end the current era of distributed NAS appliances. Toor said: "Our competitors' NAS products are derived, every one, from stand-alone NAS appliances. We're doing for storage what Cisco did for networking."

The Bobcat is priced from $19,950 (£10,600). ONStor claims that it is equivalent to a Windows, Unix and Linux-supporting EMC Celerra NS7045G NAS that costs $165,785 - three times what an equivalent Bobcat would cost. A similar HP NAS 9000 costs $97,300 - twice Bobcat's cost. A report from ESG evaluating Bobcat can be found here.