Data Storage Apparatus An apparatus (1) for storing data comprises a plurality of physical data storage disks (2). Each of the physical data storage disks (2) is divided into a plurality of sub-regions (3). The apparatus also comprises data processing means (4) configured such that: the data to be stored is divided into a plurality of data blocks, a plurality of copies of the plurality of data blocks is made and each copy is labelled with a distinct identifier, and assigned to the plurality of sub-regions (3) such that: (a) each copy of any given data block is assigned to a different physical data storage disk (2), and (b) none of the plurality of data blocks with a first identifier is assigned to the same sub-region (3) as any of the plurality of data blocks with a second identifier, for any pair of distinct identifiers.