Patent ID: 8315985

Claim:
A method comprising: generating extent group information, wherein the generating uses metadata extracted from a partition within a backup stream, the extent group information comprises information identifying one or more extent groups associated with a single data file of a plurality of data files, the data files are arranged within the backup stream, and each of the one or more extent groups comprises a plurality of extents associated with the single data file; prepending the extent group information to the backup stream; modifying an extent mapping by translating at least one offset relative to the partition into at least one offset relative to the backup stream, wherein the extent mapping comprises information identifying the data files; processing the partition within the backup stream, wherein the processing comprises sorting the data files according to a starting extent location of each data file of the data files, identifying a first data file within the backup stream, wherein the identifying the first data file locates the starting extent of the first data file, using the extent group information, identifying a second data file within the backup stream, wherein the identifying the second data file locates the starting extent of the second data file, using the extent group information, and determining whether the second data file is redundant, wherein the determining comprises determining whether the second data file is a redundant data file of the first data file, the starting extent of the each data file of the data files is identified by a first extent group within the extent group information, and the first extent group comprises information identifying one or more extents of the each data file of the data files; and de-duplicating the backup stream, wherein the de-duplicating is performed in response to a determination that the second data file is redundant, and the de-duplicating comprises removing at least one extent group associated with the second data file from the backup stream.