Abstract: A prefetch mechanism stores data in the memory allocated in a remote passive (remote) node in a High Availability active-passive node pair. A read-ahead cache that can host different parts of a file is created on both the active and the passive nodes. The system improves the performance of sequential restores by using memory available on a passive node to supplement the local (active node) memory to hold the prefetched data for the common case of large sequential restores. This extra memory overcomes issues when a current prefetch fails to keep up with the target restore performance. Filesystem redirection is thus accomplished by servicing an I/O request by sending it another node that itself caches the data.

Abstract: Embodiments of a system and method to track the locality of a file being restored at the time of prefetching; and a mechanism to dynamically adjust the prefetching parallelism, per read batch, optimally based on the locality and other heuristics, such as system load. A process tracks locality of data elements in a batched data stream, as corresponds to a number of different container IDs accessed by the data elements. The prefetch nominally works serially on the data elements, however, if the locality exceeds a threshold separating acceptable versus non-acceptable distribution of data accesses, each batch is divided into a number of smaller sub-batches that are then pre-fetched in parallel with one another.

Abstract: Embodiments of file restores in a Data Domain (DD) file system implementing a DD Bandwidth Optimized Open Storage Technology (DDBoost) library that translates application read and write request to DDBoost application program interfaces (APIs). A prefetch queue processor creates an intent to read the file. The application passes the file handle of the file, and the destination handle where the data must be read into. As the queue is processed, the prefetch for the request (handle/offset/length) is passed to the file server. The filesystem processes the request to open the file to load into memory. As the read request for the same file reaches the filesystem the file data is read from memory for writing to the destination handle. An extended DDBoost API expression is defined to pass the current path and destination path to the application.

Abstract: Embodiments of small file restore process in deduplication file system wherein restoration requires issuing a read request within an I/O request to the file system. A prefetch queue processor creates an intent to read the file, rather than opening the file upon receiving the request. During this step, the application passes the file handle of the file, and the destination handle where the data must be read into. As the queue is processed, the prefetch for the request (handle/offset/length) is passed to the file server. The filesystem processes the request to equivalently ‘open’ the file, and bring the data into memory. As the read request for the same file reaches the filesystem the file data is read from memory for writing to the destination handle.

Abstract: Embodiments of small file restore process in deduplication file system wherein restoration requires issuing a read request within an I/O request to the file system. The process places the small files in a prefetch queue such that a combined size of the small files meets or exceeds a size of the prefetch queue as defined by a prefetch horizon. A queue processor issues a read request for the first file in the queue, scans the prefetch queue to find a read request for a file at the prefetch horizon, and prefetches the file at the prefetch horizon. The prefetch queue essentially constitutes a hint from the client that a read I/O is imminent for purposes of filling the read-ahead cache and preventing a need to issue a blocking I/O operation.

Abstract: Embodiments of small file restore process in deduplication file system wherein restoration requires issuing a read request within an I/O request to the file system. The process places the files in a prefetch queue such that a combined size of the files meets or exceeds a size of the prefetch queue as defined by a prefetch horizon. A file handler disassociates prefetch streams from read streams. The handler prefetches the read operations and stores them in memory. The stream corresponding to a read will only open as the read requests hit the queue processor. As a result, the stream usage is very low, since the I/O, worker threads and the read streams are disassociated from each other.

Abstract: During a current backup of a file system of a client, a determination is that a file in the current backup includes first data regions found in a file from a previous backup, and second data regions that are new. A virtual synthetic file is generated by writing the second data regions, and synthesizing the first data regions by referencing the file from the previous backup. A request received to restore the particular file includes identifications of other files still present at client. A determination is that the particular file corresponds to the virtual synthetic file and that the other files still present at client include the file from the previous backup. The second data regions are read to send to client. A complete version of the particular file is assembled at client using the file from the previous backup, still present at client, and the second data regions.

Abstract: A request is received to restore a file at a deduplicated storage system to a client. The file resides at the storage system as a synthetic file based on a base file at the storage system. The request includes an indication that the base file is also present at the client. Metadata generated during a backup of the file to the storage system is reviewed. The metadata includes references to data determined to be in the base file at the storage system, and references to other data determined to not be in the base file at the storage system. The other data determined to not be in the base file is read from the storage system and transmitted to the client. Upon receipt, the client assembles the requested file using the base file present at the client and the other data determined to not be in the base file.

Abstract: Disclosed is a storage system comprising: receiving a first data segment and first metadata associated with the first data segment to be stored in the storage system; storing the first data segment and the first metadata in a persistent storage device of the storage system; compressing the first data segment using a predetermined compression algorithm to generate a first compressed data segment; and storing the first metadata and the first compressed data segment in a solid state drive (SSD) cache device of the storage system, including aligning the first metadata and the first compressed data segment to a page boundary of the SSD device to reduce a number of input and output (IO) operations required for accessing the first metadata and the first compressed data segment from the SSD cache device.

Abstract: Embodiments of small file restore process in deduplication file system wherein restoration requires issuing a read request within an I/O request to the file system. The process places the files in a prefetch queue such that a combined size of the files meets or exceeds a size of the prefetch queue as defined by a prefetch horizon. A file handler disassociates prefetch streams from read streams. The handler prefetches the read operations and stores them in memory. The stream corresponding to a read will only open as the read requests hit the queue processor. As a result, the stream usage is very low, since the I/O, worker threads and the read streams are disassociated from each other.

Abstract: Embodiments of small file restore process in deduplication file system wherein restoration requires issuing a read request within an I/O request to the file system. A prefetch queue processor creates an intent to read the file, rather than opening the file upon receiving the request. During this step, the application passes the file handle of the file, and the destination handle where the data must be read into. As the queue is processed, the prefetch for the request (handle/offset/length) is passed to the file server. The filesystem processes the request to equivalently ‘open’ the file, and bring the data into memory. As the read request for the same file reaches the filesystem the file data is read from memory for writing to the destination handle.

Abstract: Embodiments of file restores in a Data Domain (DD) file system implementing a DD Bandwidth Optimized Open Storage Technology (DDBoost) library that translates application read and write request to DDBoost application program interfaces (APIs). A prefetch queue processor creates an intent to read the file. The application passes the file handle of the file, and the destination handle where the data must be read into. As the queue is processed, the prefetch for the request (handle/offset/length) is passed to the file server. The filesystem processes the request to open the file to load into memory. As the read request for the same file reaches the filesystem the file data is read from memory for writing to the destination handle. An extended DDBoost API expression is defined to pass the current path and destination path to the application.

Abstract: Embodiments of a system and method to track the locality of a file being restored at the time of prefetching; and a mechanism to dynamically adjust the prefetching parallelism, per read batch, optimally based on the locality and other heuristics, such as system load. A process tracks locality of data elements in a batched data stream, as corresponds to a number of different container IDs accessed by the data elements. The prefetch nominally works serially on the data elements, however, if the locality exceeds a threshold separating acceptable versus non-acceptable distribution of data accesses, each batch is divided into a number of smaller sub-batches that are then pre-fetched in parallel with one another.

Abstract: Embodiments for a prefetch mechanism that stores data in the memory allocated in the remote passive (remote) node in a High Availability active-passive node pair. A read-ahead cache that can host different parts of a file is created on both the active and the passive nodes. The system improves the performance of sequential restores by using memory available on a passive node to supplement the local (active node) memory to hold the prefetched data for the common case of large sequential restores. This extra memory overcomes issues when a current prefetch fails to keep up with the target restore performance. Filesystem redirection is thus accomplished by servicing an I/O request by sending it another node that itself caches the data.

Abstract: Embodiments of small file restore process in deduplication file system wherein restoration requires issuing a read request within an I/O request to the file system. The process places the small files in a prefetch queue such that a combined size of the small files meets or exceeds a size of the prefetch queue as defined by a prefetch horizon. A queue processor issues a read request for the first file in the queue, scans the prefetch queue to find a read request for a file at the prefetch horizon, and prefetches the file at the prefetch horizon. The prefetch queue essentially constitutes a hint from the client that a read I/O is imminent for purposes of filling the read-ahead cache and preventing a need to issue a blocking I/O operation.

Abstract: A request is received to restore a file at a deduplicated storage system to a client. The file resides at the storage system as a synthetic file based on a base file at the storage system. The request includes an indication that the base file is also present at the client. Metadata generated during a backup of the file to the storage system is reviewed. The metadata includes references to data determined to be in the base file at the storage system, and references to other data determined to not be in the base file at the storage system. The other data determined to not be in the base file is read from the storage system and transmitted to the client. Upon receipt, the client assembles the requested file using the base file present at the client and the other data determined to not be in the base file.

Abstract: Embodiments of an instant recall process and system for long-term data stored on a cloud storage tier. Embodiments include saving a content handle of a file in a cloud storage tier as an extended attribute in a single file system namespace; moving the file from the cloud storage tier to an active storage tier for data processing; recalling the file from the active storage tier to the cloud storage tier upon completion of the data processing; using the content handle from hidden metadata for a working copy of the file; and saving a hash of a segment reference as part of the extended attribute.

Abstract: Embodiments are described for performing file restores from remote high-latency storage tiers by reading available data from a local low-latency tier in a deduplication appliance. A request to restore a previously segmented and deduplicated file can be received by a storage appliance from an application, each segment having a fingerprint. The name of the file can be looked up in an index on the storage appliance, and a first batch of fingerprints of segments of the file can be retrieved from the index. Each fingerprint can be looked up in metadata in the index to determine whether the segment corresponding to the fingerprint is available locally and therefore need not be retrieved locally. A list of local and remote prefetch segments is generated, and a prefetch request is generated for each list, if non-empty. Use of the prefetch scheme can be dynamically turned on or off.

Abstract: Embodiments of an instant recall process and system for long-term data stored on a cloud storage tier. Embodiments include saving a content handle of a file in a cloud storage tier as an extended attribute in a single file system namespace; moving the file from the cloud storage tier to an active storage tier for data processing; recalling the file from the active storage tier to the cloud storage tier upon completion of the data processing; using the content handle from hidden metadata for a working copy of the file; and saving a hash of a segment reference as part of the extended attribute.

Abstract: Embodiments are described for performing file restores from remote high-latency storage tiers by reading available data from a local low-latency tier in a deduplication appliance. A request to restore a previously segmented and deduplicated file can be received by a storage appliance from an application, each segment having a fingerprint. The name of the file can be looked up in an index on the storage appliance, and a first batch of fingerprints of segments of the file can be retrieved from the index. Each fingerprint can be looked up in metadata in the index to determine whether the segment corresponding to the fingerprint is available locally and therefore need not be retrieved locally. A list of local and remote prefetch segments is generated, and a prefetch request is generated for each list, if non-empty. Use of the prefetch scheme can be dynamically turned on or off.