A method, and corresponding system, is provided for generating replicas or copies of data objects that are used to serve data streams. The method includes determining one of the storage devices is operating at a load above a predetermined overload value. The method continues with identifying the data objects being served by data streams from the near overload storage device and then, selecting one of these served data objects for replication. To create a replica, the method includes writing data from the selected data object to another less busy one of the data storage devices, with the writing being done using data from one or more of the streams being served from the selected data object on the near-overload storage device. During replica creation, one or more streams from the selected data object provide data concurrently to a stream consumer or client device and to the replica.