Patent ID: 8615641
Filing Date: 2013-12-24
Classification: G06F

Abstract:
1. A method for creating a complete backup of user data stored on a logical disk of a data storage array at a first, later time, the method comprising: associating metadata with a first snapshot of the logical disk taken at the first, later time, the metadata comprising a mapping structure; traversing sharing information linking the first snapshot, via one or more intervening predecessor snapshots, to a baseline snapshot of the logical disk to determine differential backup information identifying corresponding disk regions of the logical disk associated with user data that has changed in the first snapshot relative to the baseline snapshot, the baseline snapshot being a complete copy of the logical disk taken at a second, earlier time that precedes the later, first time; converting the first snapshot to a differential snapshot by populating the mapping structure with the differential backup information; creating the complete backup of the user data stored on the logical disk at the first, later time based on the differential backup information, the complete backup being created by reading changed user data stored on a differential backup of the differential snapshot taken at the first, later time and reading unchanged user data stored on the baseline snapshot taken at the second, earlier time, the differential backup being populated with the user data that changed but not the user data that did not change between the first, later time and the second, earlier time.