1. A method for identifying data for placement in a storage system having a plurality of storage classes, comprising: subdividing the data into portions; determining at least one score for each portion based on a metric corresponding to access of a respective portion, wherein the at least one score for each portion is independent of scores for other ones of the portions; grouping different contiguous sets of portions into super-portions by combining a portion with a contiguous super-portion in response to the portion and the super-portion having similar scores or by creating a new super-portion, wherein each of the super-portions is optionally adjusted in subsequent iterations to remove existing portions or add new portions based on subsequent determination of similarity of scores for the portions and wherein combining a first portion with a first super-portion having a first score and a second portion with a second super-portion having a second score is independent of any difference between the first score and the second score; independently from grouping different contiguous sets of portions into super-portions, identifying sub-portions of data for placement in a first storage class based on the at least one score of a super-portion of data corresponding to the sub-portions; and determining an active component of at least one portion included in the identified sub-portions, wherein the active component is identified for placement in the first storage class, and another component of the at least one portion is identified for placement in a second storage class that is different from the first storage class.