A method for execution by a dispersed storage and task (DST) processing unit includes receiving an access request via a network. A set of possible storage units for performance of the access request are determined. A latency summarization value is determined for each of the set of possible storage units based on historical latency data for the set of possible storage units. A weight for each of the set of possible storage units is determined based on the latency summarization values to generate a plurality of weights. A probabilistic selection function is performed in accordance with the plurality of weights to select a proper subset of the set of possible storage units. A plurality of requests are generated based on the access request for transmission, via the network, to the proper subset of the set of possible storage units.