A method for allocating storage space in a volume to a new data set is disclosed. In one embodiment, such a method includes maintaining, for a volume, a record of available storage elements. The method further receives an allocation request to allocate available storage elements in the volume to accommodate a new data set. The method allocates available storage elements in the volume to the new data set to fulfill the allocation request. In doing so, the method favors storage elements that have been available for a longer amount of time over storage elements that have been available for a shorter amount of time. A corresponding system and computer program product are also disclosed.