In a virtualization system which realizes each business in an organization by a virtual machine on a physical server, a computer-readable medium storing a migration program operable on a computer forming a management server which manages migration of said virtual machine, wherein said migration program
- causes said management server to execute migration management processing of managing migration of said virtual machine,
- wherein said migration management processing includes
- assuming said physical server in which said virtual machine exists as a reference physical server, and
- assuming said physical server whose number of network hops with said reference physical server is equal to or less than the maximum number of network hops set in advance to an organization to which a business linked with said virtual machine belongs as a candidate for a migration destination of said virtual machine.