EMC's has updated its virtualisation product to allow older, less active files to be archived from network-attached storage to its Centera system, saving time and money.

Rainfinity Global File Virtualisation (GFV) version 7.0 is unique in that it comes with a preview facility that lets sysadmins play what-if scenarios using different inactive file selection policies.

Rainfinity GFV virtualises EMC and other suppliers' network-attached storage so that many storage boxes appear to be a single networked file system. This simplifies management and improves disk use. It is a rack-mounted appliance that sits to one side of the server-NAS data paths - a so-called "out-of-band" appliance.

Files can also be moved from frontline NAS storage to intermediate NAS tiers before making the final hop to Centera. If their inactive status changes then they can be moved back to NAS from Centera.

A sysdadmin could reset the criteria for inactive file selection to increase or decrease the number of files migrated to Centera. EMC's director of virtualisation marketing, Jack Norris, explained: "There is a preview mode to allow admin staff to look at a volume and see the percentage of files that could be archived. He can run a 'what-if' scenario. No other vendor has such a preview mode."

Norris emphasised that GFV 7.0 was scalable and capable of supporting enterprise-class NAS environments whereas "point archiving products" couldn't scale as well to the "hundreds of millions, even billions of files involved".

The new features come in a new file management application inside the GFV product. Users still see a single networked file system but now it includes Centera. There is also more space on the NAS boxes because older files get migrated off to Centera.

Mark Lewis, EMC's chief development officer, said of GFV: "It offers enterprise customers a single product that helps tame file system sprawl while leveraging the rich universal archiving capabilities of the EMC Centera platform."

Centera is EMC's proprietary content-addressed store (CAS). Norris said: "In future we're committed to the emerging XAM standard and the intent is that any CAS supporting XAM (eXtensible Access Method) will be supported by Rainfinity."

EMC's Rainfinity is the most popular file virtualization product in use according to an October 2006 survey by TheInfoPro. GFV v7.0 is available immediately priced from $93,000 for all hardware and software.