A computer program product and system for managing allocation of storage in a switch utilizing flow control are provided. The switch includes a plurality of ports and an internal storage divided into a plurality of storage units. The computer program product and system provide for monitoring an average number of storage units used by each of the plurality of ports over a predetermined time period, setting a threshold for the average number of storage units used by each of the plurality of ports, and allocating one or more available storage units assigned to a first port to a second port in response to storage allocation management being enabled for the second port and the average number of storage units used by the second port exceeding the threshold for the second port.