NFS Services Administrator's Guide (B.11.31.03) August 2008

However, UNIX systems use integers to represent users and groups in the
underlying filesystems stored on the disk. As a result, using string identifiers
requires mapping of string names to integers and back.
The nfsmapid daemon is used to map the owner and owner_group identification
attributes with the local user identification (UID) and group identification (GID)
numbers, which are used by both the NFSv4 server and the NFSv4 client.
On the NFS client, the nfsmapid daemon maps a numeric UID or a numeric GID
to a string representation. On the NFS server, it maps a string representation to a
numeric UID or a numeric GID.
For example, user casey with UID 121212 on an NFSv4 client whose fully qualified
name is system.anydomain.com is mapped to [e-mail]. The
NFS client sends the string representation, [e-mail], to the NFS
server. The NFS server maps the string representation, [e-mail],
to the unique ID 121212.
The nfsmapid daemon uses the user and group entries in the /etc/
nsswitch.conf file, to determine which name service to use while converting
strings and numerical values and back.
For information on how to configure the nfsmapid daemon, see nfsmapid(1M).
• File Locking
File locking support is integrated with the NFSv4 protocol. NFSv4 introduces
leases for lock management.
When a server grants a lock to control the access of a file for a specific period
of time, it is called a lease. During the lease period, the server cannot grant
conflicting access to another client.
The lock lease interval can accept values higher than the cache consistency leases.
As a result, the client requires only a smaller number of refreshes. The lease ensures
that the client does not lose the locking state.
If a client refreshes a lock, all locks held by the client with that server are validated.
This reduces the number of lease refreshes by the client from one per lock to one
per client for a specific lease.
For information on configuring NFSv4 for the server, see “Configuring the NFSv4
Server Protocol Version ” (page 29). For information on configuring NFSv4 for the
client, see “Configuring the NFSv4 Client Protocol Version” (page 49).
Sharing and Unsharing Directories
In HP-UX 11i v3, NFS replaces the exportfs command with the share command.
The share command is used on the server to share directories and files with clients.
You can use the unshare command to disable the sharing of directories with other
systems.
New Features in NFS 19