Patent ID: 8442945
Filing Date: 2013-05-14
Classification: G06F

Abstract:
1. A method, comprising: accessing a synthetic backup overlay specification that describes a backup data stream in terms of a first set of extents that may overlap, where the backup data stream can be described in terms of one or more previous backup data streams and where the data for the backup data stream is available in the one or more previous backup data streams; normalizing the synthetic backup overlay specification into a first normalized overlay specification that describes the backup stream in terms of a second set of extents that do not overlap; identifying a set of constituent files from which the second set of extents can be satisfied; creating a constituent file overlay specification from the set of constituent files, where the constituent file overlay specification describes a third set of extents in terms of binary large objects from which the second set of extents can be satisfied; normalizing the constituent file overlay specification into a second normalized overlay specification, and creating a third overlay specification from the first normalized overlay specification and the second normalized overlay specification by resolving the second set of extents using the third set of extents, where the third overlay specification has the form of a set of (B B P L refers to a length of an extent starting at P P where s and t are integers.