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Project: fedfs-utils

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This article contains a glossary of terms related to FedFS.

Administrative Client

A network host that performs domain administrative tasks remotely using the NSDB and ADMIN protocols.


A user with the necessary authority to initiate administrative tasks on one or more servers in a FedFS domain.

Domain Root Directory

The top-level directory of a FedFS domain.


A collection of independently administered fileservers that are linked together by a common namespace. Also known as a FedFS Domain.


Short for Federated File System, a set of administrative protocols and techniques for creating a file name space that can cross multiple shares on multiple fileservers, and is consistent no matter which client it is accessed from.

FedFS Domain

A file name space that can cross multiple shares on multiple fileservers. A FedFS domain is typically a single administrative entity, and has a name that is similar to a DNS domain name. Also known as a Federation.

File-access client

An entity that accesses data stored on fileservers via a standard file-access protocol such as SMB or NFS.

File-access protocol

A network filesystem access protocol such as NFSv4 or CIFS.


An entity that provides access to file storage via a standard file-access protocol such as NFS or SMB.


A collection of files and directories that are considered as a single administrative unit in a FedFS domain. Each fileset may reside at a single location, or it may be replicated to several locations. All files within a fileset are descendants of one directory. Filesets do not span filesystems.

Globally Useful Name

A pathname in the FedFS domain namespace which is the same no matter which client is used to access the file.


A link between two shared file systems. These two shared file systems might not reside on the same server. Junctions tie together separate shared file systems into a single FedFS domain namespace.

A junction's pathname is the path in a fileserver's local namespace where the junction resides. A junction's target is a list of one or more locations. Each location in this list is a replica of the same file system data.

Currently there are two types of junctions:

  • An NFS basic junction stores location information directly in each junction
  • A FedFS junction stores location information on an LDAP server so it can be shared with other fileservers

Junction Resolution

The process whereby a fileserver converts the contents of a junction into a referral for a file-access client.


A duple consisting of a fileserver host (DNS hostname or IP address) and the export path of a file system on that host. File-access clients mount a location.


A filename/directory tree that a sufficiently authorized client can access.

Namespace Database

The central repository of FedFS domain namespace information that is shared among fileservers in a FedFS domain. It is accessed via the LDAP protocol. Also known as an NSDB.

NSDB Connection Parameters

Security parameters specific to an NSDB that are used when fileservers or administrative clients communicate with that NSDB. The parameters may include a chain of x.509 certificates, including a trust anchor, for that NSDB.

NSDB Container Entry

The top-level entry on an NSDB under which FedFS-related entries are inserted. Also known as an NCE. No more than one NCE is allowed per LDAP naming context.


A fileserver response that tells a file-access client to look elsewhere for the shared file system it wants. A referral event can occur, for example, when a fileserver reports to a client that the object the client is attempting to access has moved to another fileserver. The client responds by requesting a list of locations where it can find the object.


A copy of a fileset. Replicas are used to increase availability or performance. Updates to replicas appear to occur in the same order, but do not necessarily occur simultaneously.

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