Provided are a method and apparatus capable of reducing a metadata processing time associated with address mapping performed to input/output burst data at a high speed in a virtual file system of a storage unit having a plurality of non-volatile data storage media. The method includes: determining a block group including a block included in each of a plurality of the non-volatile data storage media; determining an access unit including each page included in the determined block group; and mapping an address of input/output data to the determined block group and the access unit. Therefore, it is possible to significantly reduce an address mapping processing time in the virtual file system that may function as a bottleneck in high-speed input/output in a large-capacity storage unit.