A mechanism is provided for migrating a software image installed on a source data-processing entity to a target data-processing entity. The target data-processing entity is booted from a preliminary bootstrap program. The software image is mounted as a remote mass memory on the target data-processing entity. A primary bootstrap program of the software image is copied onto a local mass memory of the target data-processing entity. The target data-processing entity is re-booted from the primary bootstrap program thereby loading a streaming function, and serving each request of accessing a memory block on the target data-processing entity by the streaming function. In response to the memory block missing from the local mass storage, the streaming function downloads the memory block from the software image and stores the memory block into the local mass memory. Otherwise, the streaming function retrieves the memory block from the local mass memory otherwise.