DEVICE AND METHOD FOR SWITCHING THE NUMBER OF SYSTEM VERSIONS

PURPOSE:To provide a device for switching the number of system versions which can prevent the generation of return in the number of versions in a system to be driven by a server from a new birsion to an old birsion and suppress the movement of a server to irreducibly munimum frequency. CONSTITUTION:An order determining means 1 weights respective processor modules PM1 to PM3 and determines order so that the number of versions in the system is switched successively from a processor module having the lowest importance. A moving destination determining means 2 determines the moving destination of each of servers 21 to 23 included in respective modules PM1 to PM3 so as to move it to the processor module having lower importance next to the module concerned. At the time of switching the number of versions in the system, a server moving means 3 moves the server included in the processor module in which the number of system versions is to be switched to the moving destination determined by the means 2 based on those determination. A number-of-versions switching means 4 switches the number of system versions in the processor modules in the order determined by the means 1.