CAPACITY REDUCTION IN A STORAGE SYSTEM

An aspect includes implementing capacity reduction in a storage system includes for each of a candidate page and a target page in the storage system, identifying a subset of sectors having identical data or a minimum amount of non-identical data, performing a bit-wise exclusive OR (XOR) operation on sectors of the candidate page and the target page, determining entropy from results of the XOR operation. Upon determining the entropy is less than or equal to a threshold value, an aspect includes building a reference page from an XOR sector containing results of the bit-wise XOR operation, and performing a compression operation on the reference page.