Patent ID: 8719521
Filing Date: 2014-05-06
Classification: G06F

Abstract:
1. A method of crash-tolerant incremental change tracking between backups of a source storage, the method comprising: assigning each block in a source storage into one of multiple zones, each of the zones including multiple of the blocks; creating, in a nonvolatile storage, a nonvolatile zone map that represents each of the zones; tracking, in the nonvolatile zone map, each of the zones that is changed between a first point in time and a second point in time, each of the zones being marked as changed in the nonvolatile zone map upon the first receipt of a request to write to any of the blocks of the zone and prior to execution of the write request; and upon a crash of an operating system associated with the source storage and during a reboot of the operating system after the crash but prior to obtaining access to write to the source storage, activating a reverse snapshot process on the source storage to allow the source storage to be mounted while each request to write to one of the blocks of the source storage is pooled in a location other than the location of the block without actually executing the write request and with the write request falsely reported as successfully executed.