Patent ID: 8966200
Filing Date: 2015-02-24
Classification: G06F

Abstract:
1. A method for pruning free blocks out of a decremental backup in a decremental backup chain, the method comprising: identifying a decremental backup chain that includes one or more decremental backups of a source storage and a base backup of the source storage; identifying, for pruning, a target decremental backup in the decremental backup chain; retrieving one or more file system block allocation maps (FSBAMs) for points in time represented by the target decremental backup and represented by any of the other decremental backups in the decremental backup chain that depend on the target decremental backup; creating a master block allocation map (MBAM) by combining the one or more FSBAM; and pruning free blocks, corresponding to block positions that are indicated as being free in the MBAM, out of the target decremental backup.