Patent ID: 7647456

Claim:
A method, comprising: receiving a request to establish a copy relationship indicating to copy source data at a source storage location to target data at a target storage location, wherein the request indicates to copy multiple source data units to multiple target data units; determining whether a portion of the source data units defined in the request comprises target data units defined in a preexisting copy relationship; determining base source data units copied to the target data units in the preexisting copy relationship that also comprise a first part of the source data units indicated in the request in response to determining that the portion of the source data defined in the request comprises target data in the preexisting copy relationship; defining a first copy relationship to copy the determined base source data units to a first part of the target data units indicated in the request to which the first part of the source data units are copied, wherein the preexisting relationship remains after defining the first copy relationship; determining a second part of the source data units indicated in the request that does not comprise target data units in the preexisting relationship; and defining at least one additional copy relationship to copy the determined second part of the source data units to a second part of the target data units indicated in the request that are not defined in the first copy relationship, wherein the defined copy relationships are created in response to determining that the source data indicated in the request is partially within the preexisting relationship.