Embodiments of the present disclosure provide a device for data backup comprising: a secondary backup device coupled to a primary backup device, the secondary backup device further comprising: data segmentation unit operable to divide target data to be backed up into a plurality of data segments; data fingerprint generation unit operable to generate a corresponding data fingerprint for each data segment from a plurality of data segments, and providing the data fingerprint to the primary backup device for backing up the target data at the primary backup device, wherein the data fingerprint is a mapped data segment of a length less than a corresponding data segment length.