Selecting first data sets in a first storage group to swap with second data sets in a second storage group

A method for assigning data sets to storage groups, comprising:

• storing first data sets in a first storage group in a storage system;
• storing second data sets in a second storage group in the storage system;
• processing I/O activity records for jobs each indicating I/O activity for one of the jobs toward the first data sets to determine the I/O activity for the jobs toward the first data sets;
• processing job priority records indicating a priority assigned to each of the jobs;
• determining values, at least one value for each of the first data sets, la multiplying, for each of the first data sets, the I/O activity at a first data set of the data sets, indicated in the processed I/O activity records for the first data set, and the priority of the lobs assigned to handle the I/O activity to the first data set, indicated in the processed job priority records;
• and
• selecting at least one of the first data sets for which at least one of the values were determined to migrate to the second storage group based on the determined values.