A method of managing use of resources in data center comprises: determining whether first storage subsystem includes a virtual volume or a storage pool that uses a physical volume of second storage subsystem and, if yes, migrating the physical volume to first storage subsystem; determining whether any storage subsystem includes a virtual volume created directly from a physical volume and, if yes, migrating the virtual volume to another virtual volume provisioned from the storage pool of the storage subsystem; and determining whether all virtual volumes satisfy a preset service level objective and, if no, then selecting a virtual machine which has a smallest virtual machine disk file and selecting a storage pool having a largest free space, and then selecting a virtual volume of the storage subsystem which has the selected storage pool and migrating the virtual machine disk file of the selected virtual machine to the selected virtual volume.