ONC+ Release Notes

ONC+ Release Notes
What’s New in This Version of NFS
Chapter 1 7
What’s New in This Version of NFS
NFS supports the following new features:
• NFS Version 4 Protocol (NFSv4)
NFSv4 is an IETF Internet standards track protocol. It extends the existing protocol
defined by NFSv2 and NFSv3. NFSv4 supports the following features:
— COMPOUND Procedure
In NFSv4, related RPC requests are grouped into a single RPC procedure known as
the COMPOUND procedure.
The COMPOUND procedure decreases transport and security overhead because of
fewer over-the-wire trips between the client and the server. This feature is
transparent to the user.
— Delegation
The server can delegate certain responsibilities to the client. Delegation enables a
client to locally service operations without immediate interaction with the server.
Delegations can be recalled by the server. When another client requests access to the
same file, the server recalls the delegation from the first client and grants it to the
second client.
— ACLs
An Access Control List (ACL) offers stronger file security by enabling the owner of the
file to define file permissions for the file owner, the group, and other specific users and
groups.
— String Identifiers
In NFSv4, exchange of user ID and group ID information between the client and
server is in the form of strings. The nfsmapid daemon maps UID and GID values from
integer to string and string to integer.
— Locks
Locking support is integrated with the NFSv4 protocol. NFSv4 introduces leases for
lock management. When a server grants a lock to control the state of a file, for a
specific period of time, it is known as a lease.