What happens in the telephone game is that a little bit of information gets lost at each step along the path, and at the end of the chain you’ve basically lost all the information. And this happens all the time in computers, especially in data storage. Thin reclamation is the core technical challenge to thin provisioning, and the telephone game is the reason.
One of the biggest problems for thin provisioning is not the provisioning part: It’s fairly easy for a storage array to allocate on request: “I need a block; here’s some data I want you to write.” And the storage array just starts allocating, and allocating. But, the operating system never goes back and says “I don’t need that block anymore.”
Thin provisioning doesn’t take on the cost of capacity, it actually attacks the overhead of inefficient provisioning. Not all of that overhead is inefficiency, and not all of that can be tackled with thin provisioning. But some of it can. It’s a lot more of the cost than can be tackled by moving to SATA, for example. That I really like.
Since all the cool companies are offering capacity guarantees these days, I thought I might as well throw my hat into the ring and offer one, too. Starting now, I guarantee any takers an easy plan to write 50% more production data to your existing storage environment. Even better, I’ll do it with no additional hardware or software to purchase and install and no complicated terms and conditions. You won’t even have to delete anything, but if you do I’ll guarantee double your data! And I’ll only charge 50% of the deferred storage hardware and software spend, and if I can’t do it you pay nothing. What have you got to lose?