Patent ID: 7529782

Claim:
A computer-readable storage medium whose stored contents cause a data storage system to perform a method of tracking a plurality of representations of a data store at various points in time, the method comprising: creating a first representation of a data store at a first time, wherein the first representation includes information identifying a first set of data objects within the data store at the first time and locations of the identified first set of data objects at the first time; copying the identified first set of data objects and the first representation of the data store to a location remote from the location of the data store; creating a second representation of the data store at a second time after the first time, wherein the second representation includes information identifying a second set of data objects within the data store at the second time and locations of the identified second set of data objects at the second time; comparing the first representation to the second representation to identify data objects that changed from the initial time to the second time; creating a data structure mapping the changed data objects to portions of the representations of the data store that identify the locations of the changed data objects; copying the created data structure and the changed data objects to a location remote from the data store; wherein the data structure maps the changed data objects to individual data blocks storing the changed data objects.