A method and associated systems for efficient management of cloned data. One or more processors create a “child” clone of a “parent” software image. The child and parent contain identical information organized into identical sets of file blocks. To conserve storage, each child block initially points to a physical storage location already in use by a corresponding parent block, rather than requiring additional storage of its own. The first time a child block is updated, however, it will require additional physical storage. At the time of the child's creation, the processors reserve a number of physical blocks sufficient to store the contents of all child file blocks likely to be updated. A child file block is identified as likely to be updated by analyzing past volatility of a corresponding file block of the parent or of corresponding file blocks of other children of the same parent.