Abstract: A networked digital data processing system has two or more client devices, a network including a set of interconnections for transferring information between the client devices, at least one of which has a local data file storage element for locally storing and providing access to digital data files arranged in one or more client filesystems. A migration file server includes a migration storage element that stores data portions of files from the client devices, a storage level detection element that detects a storage utilization level in the storage element, and a level-responsive transfer element that selectively transfers data portions of files from the client device to the storage element.

Abstract: An improved backup storage system and method for use in conjunction with hierarchical or mass storage servers and networks is disclosed. Baseline, full and incremental backup procedures are used to save file copies. In one preferred embodiment, the baseline backup procedure is used to store copies of stable files, i.e. files that are modified less frequently, if at all. With a hierarchical storage server, such files are typically those stored on tertiary storage media, e.g. erasable optical disks, WORMs or magnetic tape. The full backup procedure stores, as full backup copies, copies of all files not in the baseline backup and files that have been changed since the time of their baseline backup. The full backup procedure also stores file identifiers and signal representative of storage locations of baseline backup copies for files which have not been changed since the time of the baseline backup.

Abstract: A digital data storage apparatus has primary, secondary and backing storage elements characterized by respectively longer access times. A level detector signals when the quantity of data in the secondary store exceeds a threshold amount. A data migrator responds by moving selected data files from the secondary store to the backing store. The apparatus also includes a baseline back-up element that stores archive copies of a set of selected data files. A full back-up element stores archive copies of those files that, (1) were originally copied to the baseline back-up set but have since changed, or (2) are not otherwise within the baseline back-up set. For those files which were originally copied to the baseline back-up set and which have not changed, the full back-up element stores pointers indicating locations of the respective files in the baseline back-up set.

Abstract: A file server system selectively stores and provides access to files across a local network. The system utilizes adaptive request batching, disk pre-allocation, and shadow inode logic to enable data writing operations to be executed at high speed, while conforming to stateless protocol requirements.