Abstract: A method of performing a file system consistency check in a distributed, segmented file system, includes: analyzing primary objects of a first segment of the file system to determine if a first primary object points to a second primary object of a second segment separate from the first segment, storing, if the first primary object points to the second primary object of the second segment, a first indication indicating that the first primary object points to the second primary object of the second segment, the first indication indicating an expected location of the second primary object; analyzing a shadow directory of the selected segment to determine an expected location of a third primary object, and an expected pointer of the third primary object indicative of a location and a name of a fourth primary object, the third primary object being contained in a segment other than the first segment; and storing a second indication indicating the expected location of the third primary object and the expected pointe

Abstract: File system coherency of a file system, particularly for system blocks, may be maintained by (i) duplicating and verifying the (system) blocks, (ii) writing (system) blocks as a sequence of atomic commands so that at any given time, there is a valid (system) block on a physical storage device, and/or (iii) defining the file system directory data structure with directory blocks, each of the directory blocks having at least one of a directory entry and a pointer, where updates to the directory data structure are performed atomically.

Abstract: Techniques are provided for producing a shadow directory structure for files or directories owned by servers whose parent directories are owned by different servers in a single distributed file system. For each file or directory whose parent directory resides on a remote server, the server owning the file or directory produces a shadow directory structure. The shadow structure may be used in a variety of ways, e.g., to access an orphan when the server owning the orphan's parent directory is offline (e.g., down, failed, or otherwise inaccessible), or to perform a partial file system consistency check (a partial fsck) to verify consistency of segments of the file system.

Abstract: A file system (i) permits storage capacity to be added easily, (ii) can be expanded beyond a given unit, (iii) is easy to administer and manage, (iv) permits data sharing, and (v) is able to perform effectively with very large storage capacity and client loads. State information from a newly added unit is communicated (e.g., automatically and transparently) to central administration and management operations. Configuration and control information from such operations is communicated (e.g., automatically) back down to the newly added units, as well as existing units. In this way, a file system can span both local storage devices (like disk drives) and networked computational devices transparently to clients. Such state and configuration and control information can include globally managed segments as the building blocks of the file system, and a fixed mapping of globally unique file identifiers (e.g., Inode numbers) and/or ranges thereof, to such segments.

Abstract: A file system (i) permits storage capacity to be added easily, (ii) can be expanded beyond a given unit, (iii) is easy to administer and manage, (iv) permits data sharing, and (v) is able to perform effectively with very large storage capacity and client loads. State information from a newly added unit is communicated (e.g., automatically and transparently) to central administration and management operations. Configuration and control information from such operations is communicated (e.g., automatically) back down to the newly added units, as well as existing units. In this way, a file system can span both local storage devices (like disk drives) and networked computational devices transparently to clients. Such state and configuration and control information can include globally managed segments as the building blocks of the file system, and a fixed mapping of globally unique file identifiers (e.g., Inode numbers) and/or ranges thereof, to such segments.

Abstract: A method of managing segments in a distributed-file system implemented by a plurality of file servers includes determining a segment of the distributed-file system controlled by a first file server for which control is to be migrated, selecting a second file server, that is different from the first file server, to take control of the segment, and moving control of the segment from the first file server to the second file server.

Abstract: Methods and systems are described comprising a plurality of nodes each comprising at least one processor and at least one storage device providing storage for the system along with an interconnect configured to establish connections between pairs of nodes. The nodes may be configured (e.g. programmed) to determine from a file identifier that identifies a particular file that a node desires to access, which of the plurality of nodes stores the desired file. The interconnect may then establish a connection between the node and the node storing the file to permit the node desiring access to access the file (e.g., read or write the file). Further, the system comprising the plurality of nodes (e.g., a cluster computing architecture) may be balanced or nearly balanced.

Abstract: A file system (i) permits storage capacity to be added easily, (ii) can be expanded beyond a given unit, (iii) is easy to administer and manage, (iv) permits data sharing, and (v) is able to perform effectively with very large storage capacity and client loads. State information from a newly added unit is communicated (e.g., automatically and transparently) to central administration and management operations. Configuration and control information from such operations is communicated (e.g., automatically) back down to the newly added units, as well as existing units. In this way, a file system can span both local storage devices (like disk drives) and networked computational devices transparently to clients. Such state and configuration and control information can include globally managed segments as the building blocks of the file system, and a fixed mapping of globally unique file identifiers (e.g., Inode numbers) and/or ranges thereof, to such segments.