US Patent 11755226 Tracking changes of storage volumes during data transfers

In some examples, a system transfers, in a first transfer operation, data of a first storage volume of a first storage location to a second storage volume for a second storage location. Responsive to a completion of the transfer of data of the first storage volume to the second storage volume, the system activates tracking information to track changes to data portions of the second storage volume, the tracking information comprising a plurality of indicators that map to respective different data portions of the second storage volume. As part of a second transfer operation following the first transfer operation, the system transfers changed data indicated by the tracking information from the second storage volume to the first storage volume, without transferring unchanged data in the second storage volume to the first storage volume.