Patent ID: 9489267
Filing Date: 2016-11-08
CPC Classification: G06F

Claim Text:
1. A method of backing up data, comprising: storing in persistent data storage a copy of a free block map as of a first time associated with a first backup; in response to the first backup, determining that an incremental backup is to be performed at a second time subsequent to the first time; determining which blocks listed as free in the free block map as of the first time have been written to since the first time based at least in part on comparing a free block map as of the second time and the previously-stored copy of the free block map as of the first time; adding one or more blocks to the persistently-stored change block tracking log based on the comparison of the free block map as of the second time and the previously-stored copy of the free block map as of the first time; and including in the incremental backup at least a subset of blocks indicated in the persistently-stored change block tracking log as having had writes made to them subsequent to the first backup and at a least a subset of blocks included in the change block log.