US Patent 9575681 Data deduplication with reduced hash computations

Techniques for data deduplication in a data storage system include comparing a first attribute of a received data page to first attributes of one or more stored data pages. In response to the first attribute matching one of the first attributes, a second attribute of the received data page is compared to second attributes of the one or more data pages. In response to the second attribute of the received data page matching one of the second attributes, a fingerprint of the received data page is compared to fingerprints of the one or more data pages. In response to the fingerprint of the received data page matching one of the fingerprints, the received data page is discarded and replaced with a reference to the corresponding data page already stored in the storage system. In response to first attribute, the second attribute, or the fingerprint of the received data page not matching, the received data page is stored.