1. An apparatus, comprising: a processor; a memory; and an interface to connect the processor, the memory, and a set of logics, the set of logics comprising: an establishment logic configured to instantiate a first one-to-many de-duplication data structure that is configured to receive a key value and to return one or more items that facilitate making one or more of, a decision concerning whether a similarity determination is to be made, and a similarity determination for a block of data to be de-duplicated, where the key value is one of, a sample taken from the block of data, the sample being less than the entire block of data, a weak hash computed from the block of data, the weak hash being susceptible to hash collisions, the weak hash being unsuitable for a duplicate determination, and an aggregation of two or more samples taken from blocks of data to be de-duplicated, where the similarity determination classifies the block of data to be de-duplicated as being one of at least three items: a unique block, a duplicate block, or a block that meets a similarity threshold with respect to a stored de-duplicated block accessible to the apparatus through the one-to-man de-duplication data structure, where the one or more items that facilitate making the similarity determination are a de-duplication data structure identifier, a de-duplication data structure ent identifier a de-duplication process identifier or a de-duplication process entry point; and a manipulation logic configured to selectively update the one-to-many de-duplication data structure by performing one or more of, adding an item that facilitates making the similarity determination, and deleting an item that facilitates making the similarity determination.