A file level striping method adds an option for indicating whether or not to support file level striping to a file creation interface in a file system, extends an inode structure to include a last disk ID field, initializes the last disk ID when the file is created in the file system, allocates a physical block based on the last disk ID when the physical block allocation is requested at the time of file I/O request in the file system, and modifies the last disk ID value to reflect the physical block allocation made by a volume manager. An apparatus using the file level striping method includes a number of disks for storing information actually, the volume manager for logically grouping a number of disks and a file system for creating files on said logical volume and performing I/O operations.