With the migration of a logical volume between virtualization apparatuses, there has been a need to change the setting of a host computer in order to access a migration destination logical volume. In a control method for a computer system including a host computer, one or more storage systems, and plural virtualization apparatuses, a first virtualization apparatus includes a first memory and manages a first logical volume to which the host computer issues an access request, and a second virtualization apparatus includes a second memory and manages a second logical volume to which the host computer issues an access request, wherein the control method associates a first real storage area on the storage system, which has been associated with the first logical volume, with the second logical volume, and stores, in the second memory, first identification information that uniquely identifies the first logical volume within the computer system.