1. A method comprises: receiving a file creation request to create a new file from portions of a set of existing files, wherein an existing file of the set of existing files includes a plurality of data segments that is stored as a plurality of sets of encoded data slices in a dispersed storage network (DSN) memory; identifying data segments from the plurality of data segments of the set of existing files corresponding to the portions of the set of existing files to produce identified data segments; identifying sets of encoded data slices of the plurality of sets of encoded data slices of the identified data segments to produce identified sets of encoded data slices; determining addressing information for the identified sets of encoded data slices from existing addressing information of the set of existing files; and generating a segment allocation table for the new file based on the addressing information of the identified sets of encoded data slices such that the new file is created without duplication of the portions of the existing files.