Patent ID: 8443159

Claim:
A computer-implemented method, at least a portion of the method being performed by a computing system comprising at least one processor, the method comprising: creating a first backup of a set of data units at a first time, the first backup comprising references to copies of one or more data units from the set of data units, wherein the copies of the one or more data units are stored in a data store that is distinct from the first backup and the first backup comprises copies of and/or references to each data unit from the set of data units; identifying one or more data units in the set of data units that have been modified since the first time; creating a second backup of each data unit from the set of data units by: providing, to the data store, copies of the one or more data units that have been modified since the first time; storing references to the data store copies of one or more data units in the set of data units that have not been modified since the first time, wherein the references to the copies of the one or more data units that have not been modified since the first time are configured such that the second backup is independent of any other backups and does not include references that refer to the first backup.