Abstract: Provided is a data processing method, which includes: in response to a logical volume receiving a write request, whether a logical address carried in the write request is occupied by a data unit in the logical volume is determined; if not, a data grain which is closest to the size of a data block and is greater than the size of the data block is determined; a new data unit is created in the logical volume by use of the logical address as an initial address and by use of the closest data grain as the length, and a logical address range occupied by the data block in the new data unit is recorded; the data block is written into an underlying storage and a written physical address is returned; and a mapping relationship between the initial address and the physical address is established and saved.