1. A system of deploying a VHD (virtual hard disk) file to a storage apparatus, the system comprising: a storage apparatus; a host computer; and a network connecting the storage apparatus and the host computer; wherein the storage apparatus receives a VHD file and checks a block size of the VHD file based on a header of the VHD file; creates a virtual volume to provide a page size which is same size as the block size of the VHD file; and performs one of (A) copying contents of the VHD file to the created virtual volume by allocating one page of the created virtual volume for each block of the VHD file; or (B) formatting the created virtual volume with a virtual volume file system, and copying the VHD file to the formatted virtual volume; and wherein the storage apparatus includes a LU-volume-VHD mapping table which contains mapping information for at least one of mapping one or more virtual volumes in the storage apparatus each to a logical unit presented by the storage apparatus to the host computer so as to accept access from the host computer to the virtual volume, or mapping one or more logical devices in the storage apparatus each to a logical unit presented by the storage apparatus to the host computer so as to accept access from the host computer to the logical device, wherein LU stands for logical unit.