Abstract: Systems. Methods, and Computer Program Products are provided for implementing transactional processing for user operations in a clustered file system (CFS). Transactional functionality is provided for user defined operations for one of writing and modifying files, and user defined write operations and individual user defined modification operations to various possible alternative files are wrapped into either a single transaction or multiple transactions individual.

Abstract: Systems. Methods, and Computer Program Products are provided for concurrent processing of transactions and read operations for achieving serialization and isolation in a clustered file system (CFS). Users, performing read only operations, are allowed to currently access the CFS while mutually excluding and serializing transactions of users affecting a same portion of the CFS. Transactions are ordered across a cluster of nodes of the CFS according to the transactions termination time.

Abstract: Systems, Methods, and Computer Program Products are provided for restoring data segments in a clustered file system (CFS). Contents of the data segments, that were modified during a transaction, which is being rolled-back to the most recent contents of the data segments prior to the transaction commencing, are restored. Locations of the most recent contents of the data segments, which are restored, are identified.

Abstract: For scalable data deduplication working with small data chunks in a computing environment, for each of the small data chunks, a signature is generated based on a combination of a representation of characters that appear in the small data chunks with a representation of frequencies of the small data chunks. The signature is used to help in selecting the data to be deduplicated.

Abstract: For scalable data deduplication working with small data chunks in a computing environment, for each of the small data chunks, a signature is generated based on a combination of a representation of characters that appear in the small data chunks with a representation of frequencies of the small data chunks. The signature is used to help in selecting the data to be deduplicated.

Abstract: Systems, Methods, and Computer Program Products are provided for implementing transactional mechanisms by a plurality of procedures on data segments by using distributed shared memory (DSM) agents in a clustered file system (CFS). A new data segment is allocated and an associated cache data segment and metadata data segments, which are allocated for the new data segment and loaded into a cache and modified during the allocating of the new data segment, are added to a list of data segments modified within an associated transaction. The DSM agents assign an exclusive permission to the new data segment.

Abstract: Systems and methods for transactional processing within a clustered file system wherein user defined transactions operate on data segments of the file system data. The users are provided within an interface for using a transactional mechanism, namely services for opening, writing and rolling-back transactions. A distributed shared memory technology is utilized to facilitate efficient and coherent cache management within the clustered file system based on the granularity of data segments (rather than files).

Abstract: For scalable data deduplication working with small data chunks in a computing environment, for each of the small data chunks, a signature is generated based on a combination of a representation of characters that appear in the small data chunks with a representation of frequencies of the small data chunks. The signature is used to help in selecting the data to be deduplicated.

Abstract: For scalable data deduplication working with small data chunks in a computing environment, for each of the small data chunks, a signature is generated based on a combination of a representation of characters that appear in the small data chunks with a representation of frequencies of the small data chunks. The signature is used to help in selecting the data to be deduplicated.

Abstract: A plurality of workers is configured for parallel processing of deduplicated data entities in a plurality of chunks. The deduplicated data processing rate is regulated using a rate control mechanism. The rate control mechanism incorporates a debt/credit algorithm specifying which of the plurality of workers processing the deduplicated data entities must wait for each of a plurality of calculated required sleep times. The rate control mechanism is adapted to limit a data flow rate based on a penalty acquired during a last processing of one of the plurality of chunks in a retroactive manner, and further adapted to operate on at least one vector representation of at least one limit specification to accommodate a variety of available dimensions corresponding to the at least one limit specification.

Abstract: A plurality of workers is configured for parallel processing of deduplicated data entities in a plurality of chunks. The deduplicated data processing rate is regulated using a rate control mechanism. The rate control mechanism incorporates a debt/credit algorithm specifying which of the plurality of workers processing the deduplicated data entities must wait for each of a plurality of calculated required sleep times. The rate control mechanism is adapted to limit a data flow rate based on a penalty acquired during a last processing of one of the plurality of chunks in a retroactive manner, and further adapted to operate on at least one vector representation of at least one limit specification to accommodate a variety of available dimensions corresponding to the at least one limit specification.

Abstract: Various embodiments for replicating deduplicated data using a processor device are provided. A block of the deduplicated data, created in a source repository, is assigned a global block identification (id) unique in a grid set inclusive of the source repository. The global block id is generated using at least one unique identification value of the block, a containing grid of the grid set, and the source repository. The global block id is transmitted from the source repository to a target repository. If the target repository determines the global block id is associated with an existing block of the deduplicated data located within the target repository, the block is not received by the target repository during a subsequent replication process.

Abstract: Systems. Methods, and Computer Program Products are provided for concurrent processing of transactions and read operations for achieving serialization and isolation in a clustered file system (CFS). Users, performing read only operations, are allowed to currently access the CFS while mutually excluding and serializing transactions of users affecting a same portion of the CFS.

Abstract: Systems, Methods, and Computer Program Products are provided for performing concurrent checkpoints from file system agents residing on different nodes within in a clustered file system (CFS). Responsibility to checkpoint a modified and a committed data segment to a final storage location is assigned to one of the file system agents. One of the file system agents, which is assigned, is the file system agent whose associated distributed shared memory (DSM) agent is an owner of the data segment.

Abstract: Systems, Methods, and Computer Program Products are provided for restoring data segments in a clustered file system (CFS). Contents of the data segments, that were modified during a transaction, which is being rolled-back to the most recent contents of the data segments prior to the transaction commencing, are restored. Locations of the most recent contents of the data segments, which are restored, are identified.

Abstract: Systems, Methods, and Computer Program Products are provided for concurrent checkpointing and modifications in a transactional clustered file system (CFS). Shadow data segments, whose contents are identical to an original data segment currently being written by a checkpoint operation, for users that require access for modification to data segments concurrently being written within a checkpoint operation.

Abstract: Systems. Methods, and Computer Program Products are provided for implementing transactional processing for user operations in a clustered file system (CFS). Transactional functionality is provided for user defined operations for one of writing and modifying files, and user defined write operations and individual user defined modification operations to various possible alternative files are wrapped into either a single transaction or multiple transactions individual.

Abstract: Systems, Methods, and Computer Program Products are provided for implementing transactional mechanisms by a plurality of procedures on data segments by using distributed shared memory (DSM) agents in a clustered file system (CFS). A new data segment is allocated and an associated cache data segment and metadata data segments, which are allocated for the new data segment and loaded into a cache and modified during the allocating of the new data segment, are added to a list of data segments modified within an associated transaction. The DSM agents assign an exclusive permission to the new data segment.

Abstract: Systems. Methods, and Computer Program Products are provided for recovering transactions of failed nodes using a recovery procedure in a clustered file system (CFS). A data segment is determined that the data segment should be copied to a final storage location by validating that an ownership of the data segment is not associated with any other operational node, via a distributed shared memory (DSM) agent. The ownership of the data segment is set to a local DSM agent.

Abstract: Systems and methods for implementing a distributed shared memory (DSM) in a computer cluster in which an unreliable underlying message passing technology is used, such that the DSM efficiently maintains coherency and reliability. DSM agents residing on different nodes of the cluster process access permission requests of local and remote users on specified data segments via handling procedures, which provide for recovering of lost ownership of a data segment while ensuring exclusive ownership of a data segment among the DSM agents detecting and resolving a no-owner messaging deadlock, pruning of obsolete messages, and recovery of the latest contents of a data segment whose ownership has been lost.