Patent ID: 7966470

Claim:
A computer-readable storage medium storing a logical volume management program that causes a computer to execute processes to allocate a storage area to a logical volume, and to function as units comprising: a first storage unit that stores configuration information on a first stage logical volume to which a correspondence relationship of storage areas between a first stage logical volume and at least one second stage logical volume is registered; a second storage unit that stores configuration information on said second stage logical volume to which correspondence relationship of storage areas between said second stage logical volume and at least one storage device is registered; an access unit that refers to said configuration information on said first stage logical volume in response to an access request designating a storage area in said first logical volume, and determines a storage area in said second stage logical volume that corresponds to the storage area in said first logical volume designated by the access request, refers to said configuration information on said second stage logical volume and accesses a storage area in said storage device that corresponds to the determined storage area in the second stage logical volume; a logical volume generation unit that (a) generates, in response to a request to extend the designated amount of a storage area of said first stage logical volume, a new second stage logical volume to which the following are allocated; (i) a storage area in said storage device allocated to said second stage logical volume and (ii) a storage area in said storage device equivalent to a difference between the storage capacity designated by said storage area extension request and the storage capacity of said first stage logical volume before extension, and then (b) registers the correspondence relationship of storage areas between said new second stage logical volume and said storage device to said configuration information on said second stage logical volume, and a storage area extension unit that extends the storage area of said first stage logical volume stored in said configuration information on said first stage logical volume to the storage capacity designated by said storage area extension request, and makes said new second stage logical volume generated by said logical volume generation unit correspond to said first stage logical volume with extended storage area.