Abstract: In a Distributed Virtual Array data storage system, data chunks making up data containers and identified by keys, which are independent of physical storage locations, are written in storage devices according to layouts specified in a layout data structure. When any of the storage devices becomes inaccessible, the chunks nominally designated to be written in the inaccessible storage devices are instead written to alternate devices. Information indicating writing to an alternate device may be included in or along with such chunks so as to make them easily identifiable during later reconstruction or re-writing to the intended storage device when it again becomes available.

Abstract: A computer-implemented method and system for deduplicating sub-chunks in a data storage system selects a data chunk to deduplicate and generates a sketch for the selected data chunk. A similar data chunk is searched for using the sketch. A set of fingerprints corresponding to sub-chunks of the similar data chunk is loaded. The set of fingerprints for the similar data chunk is compared to a set of fingerprints of the selected data chunk and the selected chunk is encoded as a set of references to identical sub-chunks of the similar data chunk and at least one unmatched sub-chunk.

Abstract: In a Distributed Virtual Array data storage system, data chunks making up data containers are stored in a key order in storage devices according to layouts specified in a layout data structure. When any of the storage devices becomes inaccessible, the storage devices iteratively return, in storage order, their stored chunks. Chunks belonging to the same container are identified and, if that container had a chunk in the inaccessible storage device, are used to reconstruct the inaccessible chunk. The chunks of the container are then stored according to an updated layout. The keys are independent of physical storage locations.

Abstract: In a Distributed Virtual Array data storage system, data chunks making up data containers are stored in a key order in storage devices according to layouts specified in a layout data structure. When any of the storage devices becomes inaccessible, the storage devices iteratively return, in storage order, their stored chunks. Chunks belonging to the same container are identified and, if that container had a chunk in the inaccessible storage device, are used to reconstruct the inaccessible chunk. The chunks of the container are then stored according to an updated layout. The keys are independent of physical storage locations.

Abstract: In a Distributed Virtual Array data storage system, data chunks making up data containers and identified by keys, which are independent of physical storage locations, are written in storage devices according to layouts specified in a layout data structure. When any of the storage devices becomes inaccessible, the chunks nominally designated to be written in the inaccessible storage devices are instead written to alternate devices. Information indicating writing to an alternate device may be included in or along with such chunks so as to make them easily identifiable during later reconstruction or re-writing to the intended storage device when it again becomes available.

Abstract: A computer-implemented method and system for improving efficiency in a delta compression process in a data storage system selects a data chunk to delta compress and generates a sketch for the selected data chunk. The method and system search for a set of candidate data chunks with a matching sketch and rank the set of candidate data chunks by degree of sketch matching. The set of candidate data chunks are tie-braked using location status data for each candidate and the selected data chunk is delta compressed with a selected candidate data chunk. The delta compressed selected data chunk is then stored in a data storage system.

Abstract: A computer-implemented method and system for improving efficiency in a delta compression process selects a data chunk to delta compress and generate matching criteria for the selected data chunk. The method and system searches for a similar data chunk using the matching criteria and loads a best match data chunk from the search. Locality data for the best match data chunk is determined and a plurality of data chunks with matching locality data are pre-fetched.

Abstract: A computer-implemented method and system for improving efficiency in a delta compression process in a data storage system selects a data chunk to delta compress and generates a sketch for the selected data chunk. The method and system search for a set of candidate data chunks with a matching sketch and rank the set of candidate data chunks by degree of sketch matching. The set of candidate data chunks are tie-braked using location status data for each candidate and the selected data chunk is delta compressed with a selected candidate data chunk. The delta compressed selected data chunk is then stored in a data storage system.