Moving data from file on storage volume to alternate location to free space

Files on a computing device are defined to include data and metadata relating to the data. Data from each file has been removed therefrom and stored at an alternate location and the file is in a reduced, ghosted form. Each of at least some ghosted files has been fully or partially reconstituted for use by retrieving the data thereof from the alternate location and associating such retrieved data with such ghosted file to form the reconstituted file. Upon receiving a trigger based on a triggering event, files are selected from among the fully and partially reconstituted files and never-ghosted files based on first predetermined selection criteria, and each of at least some of the selected files are re-ghosted.