If storage needs increase rapidly, you must "react very, very quickly" to ensure that you have enough physical storage, says Allen. The more unpredictable your needs, the better measurement and management tools you need if you adopt thin provisioning. Schulz advises looking for products that identify both the data and applications users need to track, and that monitor not only space usage but read/write operations to prevent bottlenecks.
One of the vendors in this market is IBM, which has extended thin provisioning "into all our storage controllers," says Balog. HP, which provides thin provisioning on its P4000 SANs, is set to acquire 3Par, which guarantees that its Utility Storage product will reduce customers' storage needs by 50 percent. Nexsan provides thin provisioning with its SATABeast arrays.
Before choosing a data reduction strategy, set policies to help make tough choices about when to pay for performance and when to save money by cutting your data footprint. Don't focus only on reduction ratios, Schulz says, but remember that you might get more savings with a lower reduction rate on a larger data set.
And don't be confused by vendor terminology. Compression, data deduplication, "change-only" backups and single instancing are all different ways of reducing redundant data. When in doubt, choose your storage reduction tools based on their business benefits and a detailed analysis of your data.
Scheier is a freelance writer in Swampscott, Mass. Contact him at firstname.lastname@example.org.