Abstract: A system and method for remote asynchronous replication or mirroring of changes in a source file system snapshot in a destination replica file system using a scan (via a scanner) of the blocks that make up two versions of a snapshot of the source file system, which identifies changed blocks in the respective snapshot files based upon differences in volume block numbers identified in a scan of the logical file block index of each snapshot. Trees of blocks associated with the files are traversed, bypassing unchanged pointers between versions and walking down to identify the changes in the hierarchy of the tree. These changes are transmitted to the destination mirror or replicated snapshot. This technique allows regular files, directories, inodes and any other hierarchical structure to be efficiently scanned to determine differences between versions thereof.

Abstract: In a system and method for updating a remote replicated destination file system snapshot with changes in a source file system snapshot, the snapshot being associated with a qtree (or other sub-organization of the file system volume), a qtree metadata file on the destination in provided. The qtree metadata file resides, in the destination volume, and outside the qtree structure. The metadata file stores state information with respect to each qtree. This metadata file resides at a known location in the destination volume. The metadata file can include a plurality of fixed length records having respective fields for storing various information including qtree-specific information, and can be part of a hidden metadata directory.