Information processing system and method for controlling the same

A method for controlling an information processing system including

• a plurality of first storage apparatuses configured to receive data I/O requests in file units sent from an information processing apparatus, and perform data I/O, and
• a second storage apparatus that is communicatively coupled to each of the plurality of first storage apparatuses, the method comprising:
• notifying, by one of the plurality of first storage apparatuses, prior to file migration to the second storage apparatus, to the second storage apparatus of file migration information being information relating to the file migration and including information indicating a usage rate in the one of the plurality of first storage apparatuses;
• calculating, by the second storage apparatus, an increment of a load on the second storage apparatus that is generated by the file migration based on information written in the file migration information;
• determining, by the second storage apparatus, whether the file migration is allowable based on a current load on the second storage apparatus itself and the increment,
• notifying, by the second storage apparatus, the determination result to the one of the plurality of first storage apparatuses that has notified the file migration information;
• determining, by the one of the plurality of first storage apparatuses, whether to migrate the file to the second storage apparatus based on the determination result;
• sending, by the one of the plurality of first storage apparatuses, a replica of the file to the second storage apparatus;
• acquiring, by the one of the plurality of first storage apparatuses from the second storage apparatus, storage location of the replica of the file in the second storage apparatus;
• storing, by the one of the plurality of first storage apparatuses, the acquired storage location in the one of the plurality of first storage apparatuses and deleting the file from the one of the plurality of first storage apparatuses;
• and
• referring, by the second storage apparatus, to the information indicating the usage rate in the file migration information notified from the one of the plurality of first storage apparatuses to determine whether to proceed with the file migration or not, wherein the information indicating the usage rate includes information indicating a remaining storage capacity of the one of the plurality of first storage apparatuses.