Method for allocating storage area to virtual volume

A virtualization apparatus coupled to a plurality of storage devices and a computer using data stored in said plurality of storage devices, comprising:

• a first port arranged to be coupled to a computer;
• a second port arranged to be coupled to a storage device;
• an access conversion table which is arranged to record matching relationships between virtual volumes which are targets of access requests from said computer and storage areas of said plurality of storage devices that are allocated to said virtual volumes;
• and
• a control unit;
• wherein said first port is arranged to receive a first write request from said computer addressed to a virtual volume, said control unit makes an association between said virtual volume of said first write request and a real storage area in said plurality of storage devices if there is no matching relationship in said access conversion table between said virtual volume of said first write request and said storage areas of said plurality of storage devices, said control unit converts the first write request into a second write request for the real storage area, and
• said second port is arranged to transmit the second write request converted based on said access conversion table to the real storage area associated with said virtual volume.

A method for storing data in a plurality of storage devices coupled to a virtualization apparatus which is coupled to a computer, comprising the steps of:

• issuing, in response to a request from said computer, a notice that a predetermined size of a virtual volume has been allocated to said computer,
• upon receiving a first access request issued by said computer to said virtual volume, allocating storage areas existing in said plurality of storage devices as at least a portion of said virtual volume,
• converting the first access request received from said computer to a second access request addressed to a storage device having the storage areas allocated to said virtual volume, and
• transmitting the second access request to said storage device.

A virtualization apparatus comprising:

• a first port arranged to be coupled to a computer;
• a second port arranged to be coupled to a storage device;
• and
• a control unit for creating a definition between a virtual volume which the computer seeks to access and the storage device,
• wherein the second port, upon receiving a write request issued by the computer to the virtual volume, transmits the write request, as converted according to the definition, to the storage device.