1. A method for setting up a configuration definition of a disk array apparatus that accesses connected disk devices according to an I/O request sent from a host and executes the I/O request, comprising the steps of: referring to a model correspondence table stored in a non-volatile memory for storing a maximum number of each of a host logical space, RAID space, virtual disk space and said disk devices of each model by a model name indicating a scale of said disk array apparatus and reading the corresponding maximum number of each of said host logical space, RAID space, virtual disk space and said disk devices; storing said corresponding maximum number of each of said host logical space, RAID space, virtual disk space and said disk devices into one area of a memory; securing each area in said memory for storing configuration information of the maximum number of each of said host logical space, RAID space, virtual disk space and said disk devices from the maximum number of each of host logical space, RAID space, virtual disk space and said disk devices that were stored into said one area of said memory; reading said configuration information of each of said host logical space, RAID space, virtual disk space and said disk devices of said model name from said non-volatile memory; and storing each of said configuration information from a respective starting address of said each area into each area of said memory, storing said respective starting address in said memory and creating a configuration definition table for calculating a physical block address of said disk device from a host logical block address and accessing said disk devices.