A data structure maintained in a computational device stores how many control areas splits have occurred to store a data set, wherein each control area split causes an addition of a single new control area. A command is received to add a new data record to the data set. A determination is made as to whether adding the new data record to the data set will result in a threshold for control area splits to be exceeded. In response to determining that adding the new data record to the data set will result in the threshold for control area splits to be exceeded, creating at least two new control areas in addition to continuing to use one existing control area for storing the data set.