Abstract: Embodiments of the invention relate to data replication and block allocation in a file system to support write transactions. Regions in a cluster file system are defined to support a block allocation. Blocks in the defined regions are allocated to support the data replication. A pipeline manager is provided to schedule population of the blocks in the allocated region(s) based upon network characteristics.

Abstract: Embodiments of the invention relate to data replication and block allocation in a file system to support write transactions. Regions in a cluster file system are defined to support a block allocation. Blocks in the defined regions are allocated to support the data replication. A pipeline manager is provided to schedule population of the blocks in the allocated region(s) based upon network characteristics.

Abstract: A method for data access in a multinode, shared storage data processing environment is provided by enhancing the file locking mechanism structure so as to permit nodes not normally designated as metadata controller nodes to fulfill that function for limited times thus at least temporarily eliminating the need for continual node-to-node coordination. This is particularly advantageous in the access and transfer of large files such as video files or files containing complex visualization data.

Abstract: The acquisition of a lock among nodes of a divided cluster is disclosed. A method is performable by each of at least one node of the cluster. A node waits for a delay corresponding to its identifier. The node asserts intent to acquire the lock by writing its identifier to X and Y variables where another node has failed to acquire the lock. The node waits for another node to acquire the lock where the other node has written to X, and proceeds where Y remains equal to its own identifier. The node waits for another node to acquire the lock where the other node has written to a Z variable, and writes its own identifier to Z and proceeds where the other node has failed. The node writes a value to Y indicating that it is acquiring the lock, and maintains acquisition by periodically writing to Z.

Abstract: The acquisition of a lock among nodes of a divided cluster is disclosed. A method is performable by each of at least one node of the cluster. A node waits for a delay corresponding to its identifier. The node asserts intent to acquire the lock by writing its identifier to X and Y variables where another node has failed to acquire the lock. The node waits for another node to acquire the lock where the other node has written to X, and proceeds where Y remains equal to its own identifier. The node waits for another node to acquire the lock where the other node has written to a Z variable, and writes its own identifier to Z and proceeds where the other node has failed. The node writes a value to Y indicating that it is acquiring the lock, and maintains acquisition by periodically writing to Z.

Abstract: Scalable caching of remote file data in cluster file systems is provided. One implementation involves maintaining a cache in a local cluster file system and caching local file data in the cache by fetching file data on demand from the remote cluster file system into the local cached file system over the network. The local file data and metadata corresponds to the remote file data and metadata in the remote cluster file system. Updates made to the local file data and metadata are pushed back to the remote cluster file system asynchronously.

Abstract: Asynchronous file operations in a scalable multi-node file system cache for a remote cluster file system, is provided. One implementation involves maintaining a scalable multi-node file system cache in a local cluster file system, and caching local file data in the cache by fetching file data on demand from the remote cluster file system into the cache over the network. The local file data corresponds to file data in the remote cluster file system. Local file information is asynchronously committed from the cache to the remote cluster file system over the network.

Abstract: Facilitating access to data in a network, is provided. One implementation involves maintaining a scalable multi-node file system cache in a local cluster file system, and caching file data in a cache by fetching file data on demand from a remote cluster file system into the local cached file system over the network. The local file data corresponds to file data in the remote cluster file system. Upon disconnection from the remote cluster file system, all file operations are supported at the cache. Then, upon reconnection to the remote cluster file system over the network, the remote cluster file system is synchronized with the information cached in the cache during the disconnection even in the presence of failures.

Abstract: Directory traversal in a scalable multi-node file system cache for a remote cluster file system, is provided. One implementation involves maintaining a scalable multi-node file system cache in a local cluster file system, and caching local file data in the cache by fetching file data on demand from a remote cluster file system into the cache over the network. The local file data corresponds to file data in the remote cluster file system. The local namespace emulates the remote namespace and is created on demand. Access to data further involves performing directory traversal for the cache for the remote cluster file system by creating a directory structure on demand.

Abstract: Space is allocated on data storage devices in proportion to weights associated with the storage devices. The weights can be dynamically adjusted at any time in order to accommodate changes in the system and to better utilize the storage devices. The technique used to perform the allocating is independent of the weights used by the allocating. Further, the allocation technique can accommodate general purpose data streams having varying lengths and/or varying access patterns, as well as special purpose data streams, such as video streams.

Abstract: A storage gateway is employed as part of a security enhancing protocol in a data processing system which includes at least one metadata controller node and at least one application node which is granted a time limited access to files in a shared storage system. The gateway is provided with information as to data blocks to which access is to be allowed and also with information concerning the duration of special access granted to a requesting application node. This insures that metadata cannot be improperly used, changed or corrupted by users operating on an application node.

Abstract: A storage gateway is employed as part of a security enhancing protocol in a data processing system which includes at least one metadata controller node and at least one application node which is granted a time limited access to files in a shared storage system. The gateway is provided with information as to data blocks to which access is to be allowed and also with information concerning the duration of special access granted to a requesting application node. This insures that metadata cannot be improperly used, changed or corrupted by users operating on an application node.

Abstract: A storage gateway is employed as part of a security enhancing protocol in a data processing system which includes at least one metadata controller node and at least one application node which is granted a time limited access to files in a shared storage system. The gateway is provided with information as to data blocks to which access is to be allowed and also with information concerning the duration of special access granted to a requesting application node. This insures that metadata cannot be improperly used, changed or corrupted by users operating on an application node.

Abstract: Space is allocated on data storage devices in proportion to weights associated with the storage devices. The weights can be dynamically adjusted at any time in order to accommodate changes in the system and to better utilize the storage devices. The technique used to perform the allocating is independent of the weights used by the allocating. Further, the allocation technique can accommodate general purpose data streams having varying lengths and/or varying access patterns, as well as special purpose data streams, such as video streams.

Abstract: Space is allocated on data storage devices in proportion to weights associated with the storage devices. The weights can be dynamically adjusted at any time in order to accommodate changes in the system and to better utilize the storage devices. The technique used to perform the allocating is independent of the weights used by the allocating. Further, the allocation technique can accommodate general purpose data streams having varying lengths and/or varying access patterns, as well as special purpose data streams, such as video streams.

Abstract: A system, method and computer readable medium for providing a file system snapshot with ditto address feature is disclosed. The method includes generating a file system snapshot wherein the snapshot is substantially empty. When metadata associated with a source file included in the snapshot is modified, the inode corresponding to the source file is copied to a shadow inode in the snapshot. When information is appended to a data block associated with a source file included in the snapshot, the inode corresponding to the source file is also copied to a shadow inode in the snapshot. When information in a data block associated with a source file included in the snapshot is overwritten or deleted, the inode corresponding to the source file is copied to a shadow inode in the snapshot and the original data block corresponding to the source file is copied to the snapshot.

Abstract: The present invention is directed to a method for controlling file access in a multinode, shared storage, data processing system in which a one set of nodes is capable of acting as metadata controllers and a second set of nodes are tuned for running user applications. By providing two kinds of locks operative at the file level of granularity, a mechanism is produced which permits application programs to also run on their set of metadata controller nodes. One of the locks permits read and write access to existing data blocks but precludes operations such as file deletion or file truncation. The other lock is of lower authority and permits metadata controller nodes, which can provide time limited permissions to the application nodes, to withhold locks which authorize access when requests for access are made from application nodes.

Abstract: A system, method and computer readable medium for providing a standby file system with snapshot feature is disclosed. A first snapshot of a primary file system is generated. Next, a standby file system restores the first snapshot of the primary file system in the standby file system and a snapshot of the standby file system is taken. Then, a second snapshot of the primary file system is taken and a data set capturing the differences between the first snapshot of the primary file system and a previous data set of the primary file system is generated. Subsequently, the data set is applied to the standby file system. Upon unavailability of the primary file system, the standby file system is initialized as the new primary file system. Upon recovery of the old primary file system, the old primary file system is initialized as a new standby file system.

Abstract: Space is allocated on storage devices in proportion to weights associated with the storage devices. The space is allocated by a plurality of file systems. In particular, space may be allocated on any one of the devices by one or more of the file systems. The weights can be dynamically adjusted at any time in order to accommodate changes in the system and to better utilize the storage devices. However, since more than one file system may be allocating space on one or more of the storage devices, changes in the weights are propagated to the various file systems that may utilize the information.

Abstract: Space is allocated on data storage devices in proportion to weights associated with the storage devices. The weights can be dynamically adjusted at any time in order to accommodate changes in the system and to better utilize the storage devices. The technique used to perform the allocating is independent of the weights used by the allocating. Further, the allocation technique can accommodate general purpose data streams having varying lengths and/or varying access patterns, as well as special purpose data streams, such as video streams.