A method for automatically optimizing an allocation amount for a data set includes receiving an extend request, specifying an allocation amount, for a data set in a storage pool. The method increments a counter in response to receiving the extend request. In the event the counter has reached a threshold value, the method automatically increases the allocation amount of the extend request, such as by multiplying the allocation amount by a multiplier. In the event the allocation amount is larger than a largest free extent in the storage pool, the method automatically decreases the allocation amount of the extend request to correspond to the largest available free extent. Such a method reduces or eliminates the chance that an extend request will fail, and reduces overhead associated with extending and consolidating extents. A corresponding apparatus and computer program product are also disclosed herein.