IETF-96 Proceedings

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Network File System Version 4 (nfsv4) (WG)

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Transport Area Area Director(s):

Assigned Area Director

Technical Advisor(s)


Meeting Slides:

Blue Sheets:


Request for Comments:

Charter (as of 2012-06-21):

NFS Version 4 is the IETF standard for file sharing. To maintain NFS
Version 4's utility and currency, the working group is chartered to
maintain the existing NFSv4, NFSv4.1, Federated Namespace, and
related specifications. The working group will also consider a new
NFSv4 minor version in the form of NFSv4.2 and supporting
protocols. Finally, deployment guidance will be collected for
deployments of the NFSv4 FedFS implementations and their interaction
with integration with new user authentication models.


The working group has found that as NFSv4 implementations mature and
deployments continue, clarifications to existing RFCs are needed.
These clarifications assist vendors in delivering quality and
interoperable implementations. The working group is chartered with
the vetting of the issues and determining correctness of submitted
errata. In the case that the needed changes are inappropriate for
the errata system, the working group will assist in publication of
RFCs that provide either editorial modification to original RFCs
or best practices RFCs. The completion of RFC3530bis is the first
work item. RFCs expected to generate the most discussion or activity
are: RFC 5661, RFC 5662, RFC 5663, and RFC 5664.


The NFSv4.1 Objects Layout needs some additional clarification that
are to be documented in a bis update. The working group will work
final issues and deliver an RFC for the clarifications.


For some time, the working group has discussed the requirements
for the next NFSv4 minor version. A consensus has formed within
the working group for an NFSv4.2 that contains the following:

- Server Side Copy
- Sparse Files
- Seek Hole/Data
- Space Reservations
- Application Data Blocks
- Labeled NFS
- Simple IO hinting (modeled from posix IO_ADVISE)
- Change Attribute Behaviors

This is a limited set of functionality that can be effectively
documented as an "addition" to the base NFSv4.1 protocol (RFC 5661).
Two of the items in this list, Server Side Copy and Labeled NFS,
require a new version of the RPCSEC_GSS security abstraction layer.
Thus two documents will be developed by the working group.

NFSv4 Multi-Domain Access for FedFS

As NFSv4 FedFS deployment models are discussed/planned, a significant
issue related to conflicting user identification spaces exists. User
identification collisions can occur when an NFSv4 server exports
non-domain aware POSIX file systems with separate name (NIS/LDAP)
services. These collisions can block proper FedFS operation in large
corporations or Universities with multiple naming services, or in
being a solution to join NFS name spaces in corporate acquisitions or
across University domains.

To assist in resolving these issues, the working group will deliver
three items.

First, there are a number of constraints and clarifications to the
current NFSv4.0 and NFSv4.1 protocols to fully enable cross domain

Second, there is a best practices deliverable describing methods to
work around the common current situation of non-domain aware POSIX
file systems, and in managing naming services to cooperate in
resolving remote domain POSIX UIDs and GIDs for remote user file

Third, the WG needs to track the new work in the GSS-API
authentication and authorization space (KRB WG, KITTEN WG, ABFAB WG)
to ensure NFS can take advantage of the new features that address cross
domain authentication and authorization issues.