Abstract: System and method for performing optimized restores of a multi-class file system. More actively accessed data may be assigned to higher storage classes and less actively accessed data may be assigned to lower storage classes in the multi-class file system. In a restore, the higher storage class(es) including more actively accessed data may be restored first. The multi-class file system may then be brought online for access by application(s). The lower storage class(es) may then be restored. In one embodiment, if a request for data that have not been restored is received, the file system may obtain an estimated time until restore of the requested data from the restore mechanism. The file system may then notify the application of the estimated time until restore. The application may notify a user of the estimated time, and may generate another request for the data after the estimated time has elapsed.

Abstract: System and method for providing immutable data containers in tiered storage hierarchies. Embodiments may allow fulfillment of regulatory requirements for retaining certain data through management of a user-defined policy. The policy may specify what data in the file system needs to be stored as immutable data to the immutable data container in the file system. File system data may be tracked, and data specified by the policy may be transparently and automatically stored to the immutable data container within the file system. Updates to the data specified by the policy may also be stored to the immutable data container. This may be performed without overwriting or modifying the earlier version(s) of the data stored to the immutable data container, and thus every version of the data specified by the policy may be stored to and, if necessary, reconstructed from the immutable data container.

Abstract: Provided is a method, system, and program for automatically handling an error when retrieving a file for an application. An error is detected while the application retrieves a file from the storage device. A user defined policy is checked to determine whether a backup copy should be restored, and the file is restored from the backup copy if the user defined policy indicates that the backup copy should be used.