Abstract: Embodiments of the invention relate generally to incremental computing. Specifically, embodiments of the invention include systems and methods for the concurrent processing of multiple, incremental changes to a data value while at the same time monitoring and/or enforcing threshold values for that data value. Embodiments of the invention also include systems and methods of managing utilization of a resource of a computer system having a number of threads.

Abstract: The systems and methods of the present invention provide a quiescing protocol. In one embodiment, nodes of a system utilize the protocol to complete processing until they reach a consistent state. In one embodiment, a coordinator initiates the quiescing process and the nodes communicate with each other to determine whether their messages have been processed and communicate with the coordinator to determine when all of the messages have been processed.

Abstract: In one embodiment, systems and methods are provided for nonlinear journaling. In one embodiment, groups of data designated for storage in a data storage unit are journaled into persistent storage. In one embodiment, the journal data is recorded nonlinearly. In one embodiment, a linked data structure records data and data descriptors in persistent storage.

Abstract: In one embodiment, a user or client device is connected to a distributed file system comprised of one or more physical nodes. The data on each of the physical nodes store metadata about files and directories within the file system. Some of the embodiments permit a user to take a snapshot of data stored on the file system. The snapshot may include a single file, a single directory, a plurality of files within a directory, a plurality of directories, a path on the file system that includes nested files and subdirectories, or more than one path on the file system that each includes nested files and directories. In an embodiment, a snapshot tracking data structure is maintained for efficient creation and deletion of the snapshot.

Abstract: In one embodiment, systems and methods are provided for nonlinear journaling. In one embodiment, groups of data designated for storage in a data storage unit are journaled into persistent storage. In one embodiment, the journal data is recorded nonlinearly. In one embodiment, a linked data structure records data and data descriptors in persistent storage.

Abstract: In some embodiments, storage devices, such as a storage drive or a storage node, in an array of storage devices may be reintroduced into the array of storage devices after a period of temporary unavailability without fully rebuilding the entire previously unavailable storage device.

Abstract: Systems and methods are provided for passing control of message dependencies and ordering to one or more network nodes participating in a transaction. Thus, messages can be sent to the participating nodes and the participating nodes can handle the messages according to their respective dependencies without first sending a response or waiting for the next message to arrive. In one embodiment, at least one message is flagged with a checkpoint to indicate that messages sent before the checkpoint are to be handled by the participating nodes before messages after the checkpoint. Messages may also be flagged with error-handling information. For example, a message may be marked to indicate that if the message fails, no further messages are to be sent to the node had the failure. Responses to a group of messages can be collected in a single operation.

Abstract: Systems and methods are disclosed that provide an indexing data structure. In one embodiment, the indexing data structure is mirrored index tree where the copies of the nodes of the tree are stored across devices in a distributed system. In one embodiment, nodes that are stored on an offline device are restored, and an offline device that comes back online is merged into the distributed system and given access to the current indexing data structure. In one embodiment, the indexing data structure is traversed to locate and restore nodes that are stored on offline devices of the distributed system.

Abstract: In one embodiment, a user or client device communicates with a distributed file system comprised of one or more physical nodes. The data on each of the physical nodes store metadata about files and directories within the file system. Some of the embodiments permit a user to take a snapshot of data stored on the file system. The snapshot may include a single file, a single directory, a plurality of files within a directory, a plurality of directories, a path on the file system that includes nested files and subdirectories, or more than one path on the file system that each includes nested files and directories. In some embodiments, systems and methods intelligently choose whether to use copy-on-write or point-in-time copy when saving data in a snapshot version of a file whose current version is being overwritten. In some embodiments, systems and methods allow snapshot users to return from a snapshot directory to the immediate parent directory from which the user entered into the snapshot.

Abstract: Embodiments of the invention relate generally to incremental computing. Specifically, embodiments of the invention include systems and methods that provide for the concurrent processing of multiple, incremental changes to a data value while at the same time monitoring and/or enforcing threshold values for that data value. For example, a method is provided that implements domain quotas within a data storage system.

Abstract: In one embodiment, systems and methods are provided for nonlinear journaling. In one embodiment, groups of data designated for storage in a data storage unit are journaled into persistent storage. In one embodiment, the journal data is recorded nonlinearly. In one embodiment, a linked data structure records data and data descriptors in persistent storage.

Abstract: Systems and methods are disclosed that provide an indexing data structure. In one embodiment, the indexing data structure is mirrored index tree where the copies of the nodes of the tree are stored across devices in a distributed system. In one embodiment, nodes that are stored on an offline device are restored, and an offline device that comes back online is merged into the distributed system and given access to the current indexing data structure. In one embodiment, the indexing data structure is traversed to locate and restore nodes that are stored on offline devices of the distributed system.

Abstract: Systems and methods are provided for atomic single-failure non-blocking and double-failure non-blocking commitment protocols. The protocols may be used for a variety of transactions that involve two or more parties including an initiator of the transaction, a coordinator of the transaction, and one or more participants in the transaction. The participants notify the coordinator when they are prepared to commit the transaction. The coordinator then determines when to commit or abort the transaction. If the coordinator disconnects from one or more of the participants, the participants can resolve the transaction independently. Some embodiments also include a distributor that interacts with the coordinator and the participants to resolve the transaction. If one or more parties become disconnected from the coordinator or the distributor, the participants vote to determine whether to receive instructions from the coordinator or the distributor.

Abstract: In one embodiment, a system for managing semantic locks and semantic lock requests for a resource is provided. Access to the resource is controlled such that compatible lock requests can access the resource and incompatible lock requests are queued.

Abstract: Systems and methods are provided for atomic single-failure non-blocking and double-failure non-blocking commitment protocols. The protocols may be used for a variety of transactions that involve two or more parties including an initiator of the transaction, a coordinator of the transaction, and one or more participants in the transaction. The participants notify the coordinator when they are prepared to commit the transaction. The coordinator then determines when to commit or abort the transaction. If the coordinator disconnects from one or more of the participants, the participants can resolve the transaction independently. Some embodiments also include a distributor that interacts with the coordinator and the participants to resolve the transaction. If one or more parties become disconnected from the coordinator or the distributor, the participants vote to determine whether to receive instructions from the coordinator or the distributor.

Abstract: The systems and methods maintain varying protection levels of related objects, such as when nodes of a data structure are protected at the same or greater protection level as their children nodes. In one embodiment, the nodes store data to track protection levels of their children nodes.

Abstract: Embodiments of the invention relate generally to incremental computing. Specifically, embodiments of the invention include systems and methods that provide for the concurrent processing of multiple, incremental changes to a data value while at the same time monitoring and/or enforcing threshold values for that data value. For example, a method is provided that determines whether multiple incremental changes to a data field could pass a threshold based on keeping track of a possible value range for the data field.

Abstract: In one embodiment, a user or client device is connected to a distributed file system comprised of one or more physical nodes. The data on each of the physical nodes store metadata about files and directories within the file system. Some of the embodiments permit a user to take a snapshot of data stored on the file system. The snapshot may include a single file, a single directory, a plurality of files within a directory, a plurality of directories, a path on the file system that includes nested files and subdirectories, or more than one path on the file system that each includes nested files and directories. According to one embodiment, the system stores representations of the snapshots that govern a file or directory and its descendants within metadata associated with that file or directory. In one embodiment, before modifying a file or directory, the system updates the representations of the governing snapshots by traversing the metadata of ancestors of the file or directory.

Abstract: In one embodiment, a user or client device is connected to a distributed file system comprised of one or more physical nodes. The data on each of the physical nodes store metadata about files and directories within the file system. Some of the embodiments permit a user to take a snapshot of data stored on the file system. The snapshot may include a single file, a single directory, a plurality of files within a directory, a plurality of directories, a path on the file system that includes nested files and subdirectories, or more than one path on the file system that each includes nested files and directories. In one embodiment, the metadata comprises mini-snapshots for directories representing a path from the root of the file system to the root of the snapshot. The mini-snapshots serve as stand-ins for portions of the file system which are not included in the snapshot, but which permit access to the snapshot data in an intuitive way.

Abstract: In one embodiment, systems and methods are provided for tracking events wherein an event system monitors certain areas of a system. When an event occurs in one area of the system, the event system notifies the processes listening to that area of the system of the event.