A method and system. In response to a request for a proposed additional data transfer from a source storage system to a target storage system, an estimate is made of utilization of one or more data transfer components of the source storage system and the target storage system that would occur during the proposed additional data transfer combined with other scheduled data transfers involving the source storage system and the target storage system, based in part on (i) an I/O request rate for recent actual data transfers involving the source storage system and the target storage system combined with (ii) an estimated I/O request rate for the proposed additional data transfer. It is ascertained whether the estimated utilization exceeds a corresponding utilization threshold. If so, execution of the proposed additional data transfer is postponed. If not, execution of the proposed additional data transfer is initiated.