An embodiment of a method of predicting response time for a storage request begins with a first step of a computing entity storing a training data set. The training data set comprises past performance observations for past storage requests of a storage array. Each past performance observation comprises an observed response time and a feature vector for a particular past storage request. The feature vector includes characteristics that are available external to the storage array. In a second step, the computing entity forms a response time forecaster from the training data set. In the third step, the computing entity applies the response time forecaster to a pending feature vector for a pending storage request to obtain a predicted response time for the pending storage request.