Network attached storage scales up

New technologies improve upon network attached storage, blurring the line between NAS and SAN

If you’re confused about NAS, you’re not alone. Under that acronym lie a wide range of products, from personal computing devices, to small and midsize business solutions, all the way up to ultrascalable, high-performance monsters.

In many cases, the old quick-and-dirty definition of NAS -- a specialized file server -- doesn’t cut it anymore. That description correctly identifies the basic functionality, but many new NAS solutions now do much more.

For example, clustering has taken a huge role in recent NAS developments. About a year ago, using publishing-performance benchmarks, then-startup Spinnaker proved that its SpinServer NAS product could outperform storage-networking goliaths EMC and Network Appliance when it was in a cluster configuration. NetApp has since acquired Spinnaker and plans to incorporate its technology into future high-end NAS products, proving not only that NetApp doesn’t hold a grudge, but that the Spinnaker approach to NAS is more than just hot air.

BlueArc, another innovative and relatively young player in the NAS arena, has also moved away from the traditional, general-purpose server model with its SiliconServer product line. It has created a modular structure centered on its own proprietary, hardware-based file system, called SiliconFS, which supports all major file protocols for Unix and Windows clients. Using an alternative, OS-independent file system, detached from the dated and restrictive Unix and Windows protocols, has understandably become a recurring theme in high-end NAS solutions.

Startup Panasas, maker of a revolutionary NAS solution built on Linux clusters, takes the limitations of OS-based file systems seriously. In addition to a clustered architecture, Panasas’ ActiveScale Storage Cluster features its own file system based on OSD (Object Storage Device) 1.0, a new standard that has reached the peer-review stage at the Storage Networking Industry Association.

OSD promises to make networked storage truly shareable by separating file semantics, such as name or directory path, from the actual location of data on storage devices. In essence, files stored on OSDs belong to a single namespace and can be accessed concurrently from multiple clients, an activity that has previously only been possible when files follow CIFS or NFS (Network File System) rules.

If and when OSD gains widespread acceptance, the distinction between NAS and SAN will fade even more than it has already. Perhaps only a few years down the line, storage will have become a true networked resource, with little or no concessions made to the burdens of legacy operating systems. Until then, if your business demands high-performance file serving, solutions that offer clustering and smart file systems should be at the top of your priorities.