A computer system for migrating data in a computer storage system. Data is selected to migrate from a first storage to the second storage, wherein selected files are in a resident state. Metadata is obtaining and subsets of data are ordered based on the obtained metadata, the order of the subsets of data following an expectation of update value. The subsets of data are transferring to the second storage based on the order of the subsets of data based on a predetermined schedule. Data determined as inactive is overwritten on the sequential access medium by transferred data. End data to the sequential access medium is set after a last active data is written before the one or more sets of data are determined to be inactive. The one or more sets of data determined to be inactive are deleted from the second storage and a transfer is initiated.