An object management system comprises a computer system configured to store an object (72), which may be a file. The computer system is configured to divide the object (72) into partitions (70), select partitions, and provide the selected partitions to a storage device (14) for storage. The partitions are selected by determining which partitions need to be migrated device, based on whether the partitions have been modified. The system determines this by examining a data object associated with the object. The computer system may be configured to retrieve a selected partition from the storage device.