Patent ID: 7047378

Claim:
A method for managing a relationship between one target volume and one source volume, comprising: (a) maintaining information in memory on an existing relationship between at least one source volume and at least one target volume, comprising: (i) at least one element, wherein each element represents a range of sequential data units in the volume; (ii) at least one relationship entry, wherein each relationship entry represents one relationship; (iii) at least one element pointer associating one element with one relationship entry, wherein the data units represented by the element are part of the relationship represented by the relationship entry that the pointer associates with the element; (b) adding a new relationship between at least one target volume and at least one source volume; (c) adding a new relationship entry in the memory representing the new relationship; and (d) adding one new element pointer in the memory for each element including data units included in the new relationship to associate the element with the new relationship entry, wherein the data units represented by the element are part of the new relationship.