Embodiments of the present application disclose a data writing and apparatus, a data reading method and apparatus, and a distributed object storage cluster. The data writing method includes: receiving to-be-written data sent by a client in a distributed object storage cluster (S101), and dividing the to-be-written data into a plurality of pieces of sub-data and determining a sequence number of each piece of sub-data (S102); and writing each piece of sub-data into a corresponding network hard disk (S103); for each piece of sub-data, sends a correspondence between the sequence number of the piece of sub-data and identification information of a network hard disk into which the piece of sub-data is written to the metadata server in the distributed object storage cluster (S104). Each of pieces of sub-data into which the to-be-written data is divided is written into a corresponding network hard disk. The storage characteristic of the network hard disk is that the space occupied by the stored data is the same as the size of the data itself. Therefore, the plurality of pieces of sub-data into which the to-be-written data is divided are written into respective network hard disks, which does not occupy redundant space, thereby avoiding the waste of resources. Furthermore, there is no need to wait for merging the data with other data, thereby improving the efficiency of reading and writing data.