When vendors talk about thin provisioning you will hear how it reduces CAPEX and how it increases storage admin efficiency. What you don't hear very often is how thin provisioning can reduce the cost of failure.The failure I am talking about is the failure of a new project. There is a lot of storage risk associated with a new application rollout. Without thin provisioning, storage to support this new application has to be bought, installed, powered and allocated. Like the baseball field in "Field of Dreams" you have to build it and hope they will come, but what if they don't come? You are left with a bunch of unused storage and wasted CAPEX.

There can be several causes of failure when rolling out a new application. First what if, for whatever reason, users don't use it? It happens. Think of all the failed document management or CRM rollouts. Storage was provisioned, likely over provisioned and then never used. In some cases the organization might have been able to return the application but it is highly unlikely you were able to return the storage. The storage didn't do anything wrong. Eventually it gets used for something but until then its wasted capital.

Second, what if the application rolls out just fine, there is at least moderate use of it but the application owner guessed too high on how much capacity was actually going to be needed and for some reason, which you are probably kicking yourself for now, you believed his guessestimate? That is wasted storage that will probably never be reallocated again, because it is often assigned for life, if you will, to that application. It is worse than the first example, it is wasted capital that never gets used.

Finally, what if the failure comes from success? The application is aggressively used by the users and data growth exceeds anyones expectations, more storage has to be purchased fast, even though you probably have excess capacity somewhere else in the SAN, because it is in thick volumes it can't, easily, be reallocated to the immediate need.

Our article on Thin Provisioning Basics, explains how thin provisioning addresses the obvious CAPEX issues of thick volumes but it also reduces the storage costs associated with an application gone bad. In a thinly provisioned world storage is only consumed by the application as it grows, so initially there is no need to purchase additional storage. If the application owner guesses too high on how much storage will be required, it has no impact because that capacity was never used and if the application is wildly successful, free storage space is globally available and is automatically assigned to the growing application as needed.

In all three scenarios the storage administrator with a thick provisioned storage system was sent scrambling to respond to the crisis, the storage administrator with a thinly provisioned system merely monitored his system as it automatically made him a storage hero.

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George Crump is founder of Storage Switzerland, an analyst firm focused on the virtualization and storage marketplaces. It provides strategic consulting and analysis to storage users, suppliers, and integrators. An industry veteran of more than 25 years, Crump has held engineering and sales positions at various IT industry manufacturers and integrators. Prior to Storage Switzerland, he was CTO at one of the nation's largest integrators.