Patent ID: 7398285

Claim:
An apparatus for asynchronous file-based replication of a hierarchically-indexed data store, the apparatus comprising: a hierarchically indexed data store configured to store data in a hierarchical structure corresponding to a file system; an operating system configured to access the hierarchically indexed data store and initiate write operations to the hierarchically indexed data store; a first in-memory block map for tracking changes to the hierarchically indexed data store, the first in-memory block map comprising a plurality of status indicators configured to indicate changes to blocks on the hierarchically indexed data store; a second in-memory block map for tracking changes to the hierarchically indexed data store, the second in-memory block map comprising a plurality of status indicators configured to indicate changes to blocks on the hierarchically indexed data store; a tracking module comprising a file system driver configured to monitor write operations initiated by the operating system and track file regions that have changed since a first point-in-time replication instance by updating the status indicators in the second in-memory block map in a written order; a replication module configured to asynchronously communicate data contained within file regions that have changed to a replication target as indicated by the first in-memory block map; the file system driver further configured to access the first in-memory block map instead of the second in-memory block map in response to a second point-in-time replication instance; the replication module further configured to access the second in-memory block map instead of the first in-memory block map in response to the second point-in-time replication instance and asynchronously communicate data contained within file regions that have changed to the replication target as indicated by the second in-memory block map, wherein the data is communicated in an order that is independent of the written order.