1. A method comprises: 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; retrieving at least a read threshold number of encoded data slices for each set of the plurality of sets of encoded data slices; dispersed storage error decoding the at least the read threshold number of encoded data slices for each set of the plurality of sets of encoded data slices in accordance with error coding dispersal storage function parameters to reproduce the data; 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 for each set of the plurality of sets of second encoded data slices, sending at least a write threshold number of second encoded data slices to a second set of DS units for storage therein.