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Looking for disk in all the wrong places
To understand storage consumption, you need to follow its trail from acquisition to actual use.
THE HIGH RATE of storage consumption and its associated costs continue to frustrate IT executives. The never-ending stream of approval requests for more storage invariably raises questions about where and how all of this storage is being consumed. This is typically the beginning of the quest to understand storage utilization or, more specifically, why utilization rates are so low and what can be done about it.
Source: GlassHouse Technologies
Analyzing utilization is a bit like reviewing the stats of a baseball game in the ninth inning--you have a slight chance of affecting the outcome of the game, but it's probably too late. Storage has already been allocated and any effort to reallocate or migrate it is likely to be rebuffed as too difficult or disruptive. Besides, while the actual utilization rate is important, it's just the tip of the iceberg. To better understand the problem of storage consumption, one must examine the overall request and provisioning process, and recognize the roles that data management and protection policies play.
Ask and ye shall receive
The request and provisioning process is a multistage effort, with approval, policy and fulfillment steps that often result in massive overallocation and poor utilization. How does this happen? Imperfect knowledge is one reason; we don't know how much storage we'll need, so we make an estimate and then pad that number for safety.
But why not ask for what's needed now and request more when and if it's needed? Typical purchase and allocation processes are simply not structured to support this. First, there's the challenge of acquisition. The funding vehicle for storage is often a new project, and funds may be available only at the time of the project launch. Another contributing factor is concern about the impact of making changes to a production environment, so the tendency is to add storage now to avoid future disruptions.
This was first published in July 2006