Patent ID: 7127558

Claim:
A virtualization controller which is connected to one or a plurality of storages and one or a plurality of host computers, comprising: a plurality of ports connected to one or both of said host computer and said storage; and one or a plurality of storage controllers, wherein: each of said ports and said storage controllers comprises: a virtualization processor which holds corresponding information between first identification information and second identification information, the first identification information being used for said host computer to access a storage area held by said storage, and said second identification information being used for said virtualization controller to identify said storage area, converts based on said corresponding information data having the first identification information received from the host computer into data having the second identification information, transfers the data thus converted to a storage having said storage area, converts data having the second identification information received from said storage into data having the first identification information, and transfers the data thus converted to said host computer, wherein said virtualization processor comprises: access path management information which registers a first port controlled by said host computer, a second port connected to said storage, and said virtualization processor, as an access path for each storage area of said storage, wherein when a request for changing said access path is received, said access path management information is updated, and data send/receive control is carried out between the host computer and the storage area of the storage by use of a new access path, and wherein said virtualization processor determines a type of access to a storage area being requested by an access request, manages information of the type of access being requested as access history management information and changes to said new access path based on said access history management information.