Abstract: In one embodiment, systems and methods are provided for incremental journaling. In one embodiment, order-independent operations are journaled incrementally for the same storage location. In one embodiment, partially ordered operations are journaled incrementally for the same storage location. In one embodiment, order-independent operations and partially ordered operations are journaled incrementally for the same storage location. In one embodiment, incremental journaling is used to update data that represents accounting, ctime, and parity.

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, 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 include 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. 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 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 system and method is provided for reverse lookups using a reverse lookup hint stored in metadata associated with a file or directory. The reverse lookup hint is used to retrieve an entry, comprising a name of the file or directory, which is stored in a map structure related to a parent directory of the file or directory. In an embodiment, the reverse lookup hint comprises a hash value generated from the name of the file or directory.

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 relate to systems and methods for managing stalled storage devices of a storage system. In one embodiment, a method for managing access to storage devices includes determining that a first storage device, which stores a first resource, is stalled and transitioning the first storage device to a stalled state. The method also includes receiving an access request for at least a portion of the first resource while the first storage device is in the stalled state and attempting to provide access to a representation of the portion of the first resource from at least a second storage device that is not in a stalled state. In another embodiment, a method of managing access requests by a thread for a resource stored on a storage device includes initializing a thread access level for an access request by a thread for the resource.

Abstract: Embodiments relate to systems and methods for managing stalled storage devices of a storage system. In one embodiment, a method for managing access to storage devices includes determining that a first storage device, which stores a first resource, is stalled and transitioning the first storage device to a stalled state. The method also includes receiving an access request for at least a portion of the first resource while the first storage device is in the stalled state and attempting to provide access to a representation of the portion of the first resource from at least a second storage device that is not in a stalled state. In another embodiment, a method of managing access requests by a thread for a resource stored on a storage device includes initializing a thread access level for an access request by a thread for the resource.

Abstract: In general, embodiments of the invention relate to reading data from and writing data to a storage system. Specifically, embodiments of the invention relate to a read only mode for a portion of a storage system. In one embodiment, a selective read-only mode for a portion of a storage system is implemented by monitoring a condition that may affect a subset of persistent storage in a storage system, by detecting the condition, by entering a read-only mode for the subset, and by enforcing a policy of processing write requests and read requests to the storage system, which includes processing the write requests without modifying user data stored on the subset and processing the read requests, including requests for user data stored on the subset.

Abstract: In general, embodiments of the invention relate to reading data from and writing data to a storage system. Specifically, embodiments of the invention relate to a read only mode for a portion of a storage system. In one embodiment, a selective read-only mode for a portion of a storage system is implemented by monitoring a condition that affects a subset of persistent storage in a storage system, by detecting the condition, by entering a read-only mode for the subset, and by enforcing a policy of processing write requests and read requests to the storage system, which includes processing the write requests without modifying user data stored on the subset and processing the read requests, including requests for user data stored on the subset.

Abstract: One embodiment includes a process for reverse lookups using a map structure and a structure being referenced by the map structure that comprises receiving a structure that comprises a reference to the structure and a reverse lookup hint; locating one or more entries in a map structure that correspond to the reverse lookup hint; and identifying at least one matching entry in the map structure that corresponds to the structure.

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: 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: The intelligent distributed file system enables the storing of file data among a plurality of smart storage units which are accessed as a single file system. The intelligent distributed file system utilizes a metadata data structure to track and manage detailed information about each file, including, for example, the device and block locations of the file's data blocks, to permit different levels of replication and/or redundancy within a single file system, to facilitate the change of redundancy parameters, to provide high-level protection for metadata, to replicate and move data in real-time, and to permit the creation of virtual hot spares among the smart storage units without the need to idle any single smart storage unit in the intelligent distributed file system.

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: Embodiments of the disclosure relate generally to file systems. Specifically, certain embodiments include systems and methods for reading objects in a file system. In some embodiments, a first processing thread traverses a portion of a file system and represents file system objects in a data structure. A portion of the data and/or metadata associated with the represented objects may be prefetched to a memory. In some embodiments, a second processing thread consumes the objects represented in the queue. For example, in a file system backup embodiment, the second processing thread may transfer data and/or metadata associated with the objects to an archive target.

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: 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.