1. A method for performing data storage optimizations comprising: determining a reserved workload for a first of a plurality of storage tiers, each of the plurality of storage tiers characterized by a set of one or more attributes, wherein said first storage tier includes performance characteristics which are any of incomplete, unknown, and unable to be predictively modeled for various workloads, said plurality of storage tiers including the first tier and a remaining set of one or more additional storage tiers; modeling performance of a first workload distributed among the remaining set of storage tiers, wherein said first workload represents a total workload less the reserved workload; determining one or more data movements in accordance with said modeling, each of said one or more data movements moving a data portion from a first physical device of one of the plurality of storage tiers to a second physical device of another of the plurality of storage tiers; and performing at least a first of the one or more data movements that moves a data portion between two of the plurality of storage tiers, and wherein said determining the reserved workload further comprises: selecting a second storage tier from the remaining set, wherein said second storage tier is ranked as having a minimum classification ranking of all storage tiers in the remaining set; and determining a difference between a first average observed response time for the first storage tier and a modeled average response time for the second storage tier.