Thin Provisioning: The Skinny on Storage

The mounds of extraterrestrial data collected by NASA satellites and rockets raise a down-to-earth question: What should be done with all that information?

Data storage is a major challenge for Adrian R. Gardner, CIO for NASA’s Goddard Space Flight Center in Greenbelt, Md. He says that NASA, much like the rest of the federal government, is exploring how it can better — and more inexpensively — utilize data storage capacity.

Having adopted a storage area network several years ago, Goddard is piloting thin provisioning technology. The SAN treats all attached storage devices as one virtual pool, and thin provisioning ensures that the storage devices are utilized to almost full capacity before IT managers have to expand capacity. The combined technologies enhance security, as data is automatically and safely backed up. The upgrades should result in significant cost savings and lower the footprint of Goddard’s data centers, Gardner says.

Turn to Thin Provisioning

As the data storage needs of federal agencies continue to grow, experts say more of them are turning to thin provisioning.

With traditional technology, discrete blocks of storage are set aside for every application or user who might need it. The tendency of users to overestimate storage needs frequently results in an over-allocation of storage capacity. The result is that utilization rates can be as low as 20 percent.

Mark Peters, a senior analyst at the Enterprise Strategy Group, says the inefficiency is like a bus that won’t let on new riders despite being only 20 percent full because passengers are saving seats for friends and family members, including the unborn, who might want to ride in the future.

“The old way of provisioning led to appalling levels of utilization,” Peters says. “If other resources in the world were used as poorly as storage space once was, people would be laughed at.”

Inefficiency was tolerable when IT constituted a small part of organizations’ operations and budgets, and the cost of storage generally declined at a rate that offset increased use. Recently, however, the cost of storage hasn’t fallen fast enough to compensate for surging IT use and the corresponding increase in demand for storage.

“Over the last few years there has been a massive focus on doing things not just effectively, but more efficiently in terms of using fewer resources,” Peters says. “The big mantra in IT is to do more with less.”

Thin provisioning delivers physical storage on demand. If a particular application experiences a rapid spike in storage needs, the system automatically dips into the shared storage pool to provide it. This lets IT managers allocate considerably more storage than the physical capacity they actually possess. Technicians can easily monitor the system, or any part of it, from a single computer screen. As the networked storage devices approach full capacity, the system alerts technicians to buy more.

The U.S. District Court in Kansas adopted thin provisioning to avoid the complication of adding new storage to a system in which hard drives and other data storage devices were linked to an older network.

Having invested in a Compellent SAN with thin provisioning two years ago, 70 percent of the administration’s 6 terabytes of data is now handled with thin provisioning, and the rest soon will be as well, says Michael Keyes, the court’s assistant IT manager.

The big benefit of the new technology is that the court doesn’t have to go back and redesign the system when it needs to add more storage. “You can set it for an extremely large size, and just add storage as needed,” Keyes notes.

The upshot is considerable cost savings. “The storage I can buy in two years, when I actually need it, will generally be cheaper than if I bought it today,” says Keyes.