Raid data storage system

A data storage system, particularly but not limited to a RAIDed data storage system, is provided. The data storage system includes at least a data storage module having at least a first I/O port and a second I/O port. The storage of the data storage module includes at least a first area and a second area which are pre-determined. The data storage system further includes at least a first controller module and a second controller module, where the first controller module is directly connected to the first I/O port to access the first area, and the second controller module is directly connected to the second I/O port to access the second area. Notably, the data storage module could be expanded to have more than two I/O ports.