Homes, national landmarks, disaster zones: all popular destinations on Google Earth, the search giant’s free ‘virtual globe’. But even with a market capitalisation of over $100 billion, Google cannot afford to launch its own imaging satellites. The images are provided by several third parties, with many of the real close-ups sourced from Digital Globe.

Digital Globe’s QuickBird satellite, launched in 2001, provides the highest resolution satellite images available commercially: each pixel represents just two square feet on the ground. The fixed satellite can cover any region on Earth within three days of the company receiving a commission – useful for property and natural resource surveyors, and agricultural and forestry organisations.

The satellite can take up to 50 photos a day, each four to six gigabytes in size, making Digital Globe’s storage requirements among the world’s largest – and fastest growing. The image library already runs into several hundred terabytes, says Digital Globe’s director of corporate communications, Chuck Herring: “We are already talking about petabytes [250 bytes].”

Yet even though the company will launch new satellites in 2006 and 2008, sending down hundreds more images a day, Herring is confident that it does not need to worry about storage for the next five to ten years. “By understanding the exact specs of each satellite we are able to gauge where we can go with storage capabilities and sizing aptly. Our storage needs are pretty predictable, but storage is key to this business,” he says.

Storage demands increased 200% over 2004-5; expanding capacity was vital for Digital Globe to take advantage of the boom in global imagery of recent years. “Internet mapping has raised the bar for geospatial information because so many people are aware of it now,” says Herring, thanks particularly to Google Earth.

Responding to that growth, Digital Globe updated its storage infrastructure to take advantage of storage area network (SAN) technology. That has enabled it to meet the uptime, data volume and processing performance requirements of all its new business, at a cost of “several million pounds”. The company consolidated its 200TB production capacity onto seven Hitachi storage arrays, underpinned by an ADIC SAN file system.

“The infrastructure itself was not overly complex, but getting all the applications working to one approach took a lot of planning and execution effort,” says Luc Tredel, director of IT operations at Digital Globe. “We had to migrate from a piecemeal set of file handling processes to a single coherent solution. But the effort was well worthwhile: we now have a highly manageable and scalable storage subsystem underpinning our ground systems.”

ADIC’s StorNext data management software has solved the problem of having to move and copy raw image data several times during the assembly of large images from multiple pictures – historically, a slow and unreliable process. StorNext streamlines workflow through up to 20 specialised applications by creating a common 20TB of shared cache.

This, along with a new 10GB Ethernet network, has enabled jobs to be completed up to 400% faster, as the system requires less administration. It is also more rapidly adaptable, helping the the company respond to new opportunities.