Patent ID: 8713272

Claim:
A method of handling a copy process comprising: for a point in time copy from a source disk to a target disk that are part of a cascade of disks, wherein the cascade represents a series of point in time copies between the disks, creating a map specifying the point in time copy from the source disk to the target disk; in response to determining that a primary fdisk does not exist for the source disk, creating the primary fdisk for the source disk, wherein the primary fdisk for the source disk comprises an object that links the source disk to maps upstream and downstream within the cascade; in response to determining that a primary fdisk does not exist for the target disk, creating the primary fdisk for the target disk, wherein the primary fdisk for the target disk comprises an object that links the target disk to maps upstream and downstream within the cascade; and in response to determining that the primary fdisk for the target disk does exist, converting the existing primary fdisk for the target disk into a secondary fdisk; and creating a new primary fdisk for the target disk.