A data archiving controller automatically determines a whether a main storage devices has usage ratio in excess of a maximum limit and if an archiving or backing storage device has sufficient directory space to accept files from the main storage devices. The data archiving controller then determines using fuzzy logic the number of files to be transferred from the main storage devices to the backing storage devices. The data archiving controller has a set allocating apparatus in communication with the main storage device and the backing storage devices to receive retention device usage parameters for classification within classification sets. A membership rules retaining device contains the classification parameter defining rules by which the retention device usage parameters are assigned to the classification sets. The archiving controller has a rule evaluation apparatus for determining a quantity of data to be archived. The quantity of data to be archived is based on evaluation rules determined by the classification sets. A data designation apparatus designates the number of files to be archived and then designates the files to be transferred between the main storage device and backing storage devices.