Products typically arrive in large units, such as unit-loads, and standard or custom containers, or pallets, which cause the related labour and handling activities to be less expensive. Incoming products must be put away, which is the most significant warehouse function. The put-away process entails a set of interdependent decisions [2]: given a warehouse configuration (based on the layout parameters of Fig. 1), how much inventory should be held for a generic SKU (the so-called allocation in Fig. 1), and where should it be stored (the so-called assignment in Fig. 1)?