Methods and apparatus to compress a dataset are disclosed. A disclosed method comprises: obtaining a first block of a dataset to be compressed; computing a proxy for at least a portion of the first block; comparing the proxy to a set of proxies representative of previously stored blocks; and, if the proxy for the at least the portion of the first block matches a proxy in the set of proxies, storing a data structure that maps the at least the portion of the first block to at least a portion of a previously stored block associated with the matching proxy without storing the at least the portion of the first block.