A data processing apparatus includes a calculating unit configured to calculate a compression ratio when a block selected from among the plurality of blocks is compressed; a determining unit configured to determine whether a block is to be compressed by comparing the calculated compression ratio with a threshold; a recording unit configured to record the block on the storage device in a compressed or uncompressed state on a basis of a result of the determination; a management information creating unit configured to create a management information in association with data identification information for identifying the data, state information indicating a compressed or uncompressed state is recorded to the management information in association with each block, when the each block is recorded on the storage device; and a storage processing unit configured to store the management information created by the management information creating unit on a memory.