A method begins by processing module determining data to migrate, wherein the data is stored as a plurality of sets of encoded data slices in a first set of dispersed storage (DS) units. The method continues with the processing module retrieving at least a read threshold number of encoded data slices for each set of the plurality of sets of encoded data slices and dispersed storage error decoding the at least the read threshold number of encoded data slices in accordance with error coding dispersal storage function parameters to reproduce the data. The method continues with the processing module dispersed storage error encoding the data in accordance with second error coding dispersal storage function parameters to produce a plurality of sets of second encoded data slices and sending at least a write threshold number of second encoded data slices to a second set of DS units for storage therein.