Abstract: Various methods and systems for implementing a file change log in a distributed file system are disclosed. In one embodiment, a method involves operating a distributed file system that presents a namespace and maintaining a file change log for the namespace. Operating the distributed file system involves executing an instance of a file system on each of several nodes. Maintaining the file change log can involve maintaining a single file change log for the namespace. Updates to the single file change log can be handled by a primary node or controlled using a locking mechanism. Alternatively, several private file change logs (e.g., one per node) can be maintained, and these private file change logs can be merged into a single file change log (e.g., by a primary node).

Abstract: Various embodiments of methods and systems for assigning symbolic names to data streams within a file are disclosed. In one embodiment, a method involves receiving a request to access a file that includes multiple data streams and then selecting one of the data streams to be accessed, based on the symbolic name. In response to identifying that one of the data streams is associated with the symbolic name, that data stream is accessed.

Abstract: A method and apparatus for utilizing a file change log is described. In one example, the access of a file is initially detected. The identifier of the entity accessing the file is recorded. Similarly, an indicia of identifying at least one portion of the file that was accessed by the entity is recorded. The file change log is then updated to reflect the identifier and the indicia.

Abstract: A method and apparatus for creating and using a policy-based file access/change log. Using the policy-based techniques, specific objects within the file system are selected for logging within an access/change log. These selected objects are then processed to identify attributes of the selected objects that are to be logged such that a policy is created regarding the objects to be logged and the attributes of those objects. Lastly, the policy is applied to the object either by having a separate object (file) created that is related to the object to be logged that identifies the policy for logging, or by attaching certain attributes directly to the object such that access to the object identifies the logging policy for that object. When an object that uses policy-based logging is changed, the object access/change log policy is utilized to log only the information that is identified in the policy.