Methods, systems, and techniques for data compression. A cluster fingerprint of an uncompressed data block is determined to correspond to a cluster fingerprint of a base block stored in a base array. This determining involves looking up the cluster fingerprint of the first base block from the base array using the cluster fingerprint of the first uncompressed data block. The difference between the uncompressed data block and the base block is determined, and a compressed data block is encoded using this difference. The compressed data block is then stored in a data array.