Tiered storage is one of those things that is a means to an end—and not an end in itself. The reason tiered—not just tiered, but effectively and efficiently tiered—storage is becoming more crucial (indeed, a prerequisite for many organizations) is a simple matter of economics. After all, if storage were free, then everything would logically be stored on the fastest devices available. Capacity would be unlimited and cost no issue. Yes, there are some practical issues around connectivity and access, but you get the point: the only reason we have long sought the nirvana of an effective storage hierarchy is that storage isn’t free and consequently, we need to make choices and allocate data to appropriate levels and types (i.e., costs) of storage.

Now, with the rate of storage growth outstripping the rate of its price decline, tiering and storage economics are back on the agenda—still not because they are inherently desired, but because of what they can deliver: namely, lower costs, better business outcomes, and a pragmatic route to cope with massive storage growth. These are the "economics of necessity." Of course, once good tiers and tools that make effective tiering feasible (and the economics compelling) exist, then users also start looking at the "economics of opportunity"—in other words, if tiering is something that can be embraced rather than avoided, then additional value can be sought and overall efficiency can be increased. Tiered storage can move from something that users do because they have to (as little as they can get away with) to something they do because they want to.