A method includes receiving a command for migration of a workload partition having multiple processes from a source machine to a target machine. The method includes executing, for each of the multiple processes at least partially in parallel, an operation to create checkpoint data. The operation to create the checkpoint data provides an estimation of a size of the checkpoint data that is needed for migration, wherein the operation to create the checkpoint data is independent of storing the checkpoint data in the file. The method includes allocating areas within the file for storage of the checkpoint data for each of the multiple processes. The method includes storing the checkpoint data, for each of the multiple processes at least partially in parallel, into the areas allocated within the file based on offsets in the file for each of the multiple processes.