1. A method of checking, in a virtual machine system comprising a first physical computer for executing a first virtual machine, a second physical computer capable of executing a virtual machine, and a management server for managing the virtual machine system, whether the first virtual machine can be executed by the second physical computer, the method comprising the steps of: acquiring, by the management server, information about first logical resources accessed by the first virtual machine via a physical adaptor of the first physical computer; acquiring, by the management server, setting information set to the physical adaptor of the first physical computer so that the first virtual machine accesses the first logical resources; listing second logical resources that are accessible to the first virtual machine via a physical adaptor of the second physical computer in a case where the first virtual machine is executable by the second physical computer and the setting information is set to the physical adaptor of the second physical computer, wherein the listing step comprises: (a) determining, by the second physical computer, whether a first physical adaptor of the second physical computer for accessing the second logical resources is exclusively assigned to a second virtual machine executable by the second physical computer; (b) when the first physical adaptor of the second physical computer is determined to be exclusively assigned to the second virtual machine, excluding, by the second physical computer, the first physical adaptor of the second physical computer from the second logical resources to be listed; (c) listing, by the second physical computer, the second logical resources that are accessible to the first virtual machine via a second physical adaptor of the second physical computer yet to be assigned to the second virtual machine; and (d) acquiring, by the management server, information on accessibility by the first virtual machine to the listed second logical resources through exclusive assignment of the second physical adaptor of the second physical computer; and determining, by the management server, whether the first virtual machine can be executed by the second physical computer by comparing the acquired information about the first logical resources and the listed second logical resources.