US Patent 9563463 Computer system and control method therefor

A computer system includes a plurality of server apparatus, a plurality of storage apparatus, a management computer, and a management computer. The management computer stores a server rank which represents a rank of a throughput of a server apparatus, and a storage rank which represents a rank of a throughput of a storage apparatus. Each of the plurality of server apparatuses executes a plurality of virtual machines, and stores a required server rank and a required storage rank. If it is determined that a virtual machine should be migrated on the basis of a load on the plurality of virtual machines, the management computer selects a server apparatus having a server rank equal to the required server rank as a destination server apparatus, and selects a storage apparatus having a storage rank equal to the required storage rank as a destination storage apparatus.