Abstract: Provided are a computer program product, system, and method for selecting first data sets in a first storage group to swap with second data sets in a second storage group. First data sets are stored in a first storage group and second data sets are stored in a second storage group. A determination is made for a value for each of at least one of the first data sets based on at least one priority of at least one job processing I/O activity at the first data set. At least one of the first data sets for which the value was determined is selected to migrate to the second storage group based on the value.