Abstract: A file system allows a different checksum algorithm to be used for different extents of a file system object independently of other extents of the file system object. The checksum algorithm can be a selectable attribute of an extent or range of extents of a file system object, such that some extents of a file system object can use a first checksum algorithm, while other extents of the file system object can use a second checksum algorithm. An extent of the file system object also may have no associated checksum algorithm. The file system stores, for each extent of a file system object, data indicating a checksum for the extent and an indication of any checksum algorithm used for the extent.

Abstract: File system-awareness of ghosting performed by one or more tiering engines allows a file system to receive and store metadata indicating an identifier of the tiering engine ghosting the file extents and a storage location of the ghosted file extents for later use by the tiering engine. The file system is able to receive and process requests to read and write to a file having ghosted extents.

Abstract: To provide an operation that can quickly copy or rearrange a file, a file system allows stored data to be shared among two or more files or within a file. The file system provides an operation that allows an extent from one file to be copied into an extent of another file, or into a different extent in the same file if the extents do not overlap. To support such an operation, the file system tracks the storage locations for stored data for extents of a file, and whether the stored data for an extent of a file is shared with any other file or by another portion of the same file. When stored data is shared, writing to an extent of a file that refers to the shared stored data invokes a write operation to a new extent on the storage device, and the tracked information for the affected extents is updated.

Abstract: A file system allows a different checksum algorithm to be used for different extents of a file system object independently of other extents of the file system object. The checksum algorithm can be a selectable attribute of an extent or range of extents of a file system object, such that some extents of a file system object can use a first checksum algorithm, while other extents of the file system object can use a second checksum algorithm. An extent of the file system object also may have no associated checksum algorithm. The file system stores, for each extent of a file system object, data indicating a checksum for the extent and an indication of any checksum algorithm used for the extent.

Abstract: To provide an operation that can quickly copy or rearrange a file, a file system allows stored data to be shared among two or more files or within a file. The file system provides an operation that allows an extent from one file to be copied into an extent of another file, or into a different extent in the same file if the extents do not overlap. To support such an operation, the file system tracks the storage locations for stored data for extents of a file, and whether the stored data for an extent of a file is shared with any other file or by another portion of the same file. When stored data is shared, writing to an extent of a file that refers to the shared stored data invokes a write operation to a new extent on the storage device, and the tracked information for the affected extents is updated.

Abstract: A method and system for increasing server cluster availability by requiring at a minimum only one node and a quorum replica set of replica members to form and operate a cluster. Replica members maintain cluster operational data. A cluster operates when one node possesses a majority of replica members, which ensures that any new or surviving cluster includes consistent cluster operational data via at least one replica member from the immediately prior cluster. Arbitration provides exclusive ownership by one node of the replica members, including at cluster formation, and when the owning node fails. Arbitration uses a fast mutual exclusion algorithm and a reservation mechanism to challenge for and defend the exclusive reservation of each member. A quorum replica set algorithm brings members online and offline with data consistency, including updating unreconciled replica members, and ensures consistent read and update operations.