In a storage system in which computers are connected via a network, in order to avoid a state where communication quality is degraded due to poor performance of an apparatus constituting the network, for a transfer data amount, an amount of data sent out from a storage apparatus is suppressed. Moreover, the storage apparatus inhibits a read-ahead process, in accordance with the suppression of the sending out of the data. Furthermore, proper load allocation is realized by migrating a logical storage unit provided by the storage, to another network interface or a second storage apparatus, without changing a configuration of the network.