1. A server system including: a server apparatus transmitting and receiving file data based on an access request transmitted from a client apparatus; and a management apparatus managing the server apparatus, wherein the server apparatus comprises: a plurality of virtual server parts controlling transmission and reception of the file data independently for each of the predetermined client apparatuses; a data flow configuration part configuring a data flow for each of the file data transmitted and received by the virtual server parts based on a command from the management apparatus; and a load control part controlling a data flow for each of the file data to control load of the virtual server parts based on the data flow for each of the file data configured by the data flow configuration part.