Patent ID: 7467282

Claim:
A method for migrating a traditional volume to a virtual volume without data copying, the method comprising: selecting a traditional volume index node; and converting a structure of the traditional volume index node to a dual address structure of a virtual volume index node, wherein the virtual volume index node includes physical address information and virtual address information, wherein converting the structure of the traditional volume index node to the dual address structure of the virtual volume index node comprises: determining one or more physical addresses for a corresponding one or more data blocks based, at least in part, on a traditional volume buffer tree of the traditional volume index node; generating, at least in part, a dual address buffer tree having the virtual volume index node; copying the one or more physical addresses for the corresponding one or more data blocks to the dual address buffer tree; and allocating a virtual address for each of the one or more physical addresses, wherein each virtual address specifies a virtual volume block corresponding to one of the one or more physical addresses.