Patent ID: 7603391

Claim:
A method for backing up a file system, comprising: generating a first snapshot of the file system at a first time; receiving, by a network adapter, storage operations to write new data to the file system; generating a second snapshot of the file system at a second time, the second snapshot including the new data; scanning a logical file block index of each snapshot to detect changed pointers in order to determine a one or more blocks which have changed between the first snapshot and the second snapshot, the scanner adapted to walk down a hierarchy of pointers associated with each logical block file index and retrieve only blocks with volume block numbers that are different in the second snapshot from the volume block numbers in the first snapshot while bypassing blocks having unchanged volume block numbers, in order to retrieve only data blocks which have changed between the first snapshot and the second snapshot; and copying, in response to scanning the logical file block index, data of the file system which have been changed between the first snapshot and the second snapshot to a backup copy of the file system, the backup copy stored in a persistent memory of a destination computer.