mount_nfs.1m (2010 09)

m
mount_nfs(1M) mount_nfs(1M)
protocol.
To specify NFS Version 2, set NFS_version_number to be 2.
To specify NFS Version 3, set NFS_version_number to be 3.
If the
-F option and vers=
are both specified, vers= overrides the -F
option.
wsize=n Set the write buffer size to n bytes. The default value is
32768 when using
Version 3 of the NFS protocol. The default can be negotiated down if the
server prefers a smaller transfer size. When using Version 2, the default
value is
8192.
-q Prevent printing a warning message for unknown specific_option . If the
-q option is not specified,
and an unknown specific_option is encountered, the
mount utility prints a warning message and
processes the next one. The
-q option prevents printing the warning message.
-O Overlay mount. Allow the file system to be mounted over an existing mount point, making the
underlying file system inaccessible. If a mount is attempted on a pre-existing mount point without
setting this flag, the mount will fail, producing the error
device busy.
Options (umount)
The
umount options are as follows:
-a Attempt to unmount all NFS file systems described in /etc/mnttab.
-d Print debug messages to stderr. This option is to be used by HP support engineers.
-f Forcibly unmount a file system. If this option is not specified, the
umount utility does not allow a
file system to be unmounted if a file on the file system is busy. Using the
-f option can cause data
loss for open files; programs which access files after the file system has been unmounted will get an
error (EIO).
NFS FILE SYSTEMS
Background versus Foreground
File systems mounted with the
bg option indicate that mount is to retry in the background if the server’s
mount daemon does not respond. See mountd (1M). mount retries the request up to the count specified
in the retry=n option. Once the file system is mounted, each NFS request made in the kernel waits
timeo=n tenths of a second for a response. If no response arrives, the time-out is multiplied by
2 and
the request is retransmitted. When the number of retransmissions has reached the number specified in
the
retrans=n option, a file system mounted with the soft option returns an error on the request; one
mounted with the hard option prints a warning message and continues to retry the request.
Hard versus Soft
File systems that are mounted read-write or that contain executable files should always be mounted with
the
hard option. Applications using soft mounted file systems can incur unexpected I/O errors, file
corruption, unexpected program core dumps, and delays in system reboot/shutdown. The soft option is
not recommended.
Authenticated requests
The server can require authenticated NFS requests from the client. The
sec=dh authentication (Diffie-
Hellman public key system) might be required. See nfssec (5).
URLs and the public Option
If the
public option is specified, or if the resource includes an NFS URL, mount attempts to connect to
the server using the public file handle lookup protocol. See WebNFS Client Specification, RFC 2054 .If
the server supports the public file handle, the attempt is successful; mount does not need to contact the
server’s rpcbind and the mountd daemons to get the port number of the mount server and the initial
file handle of pathname , respectively. See rpcbind (1M) and mountd(1M). If the NFS client and server
are separated by a firewall that allows all outbound connections through specific ports, such as
NFS_PORT, then these ports enable NFS operations through the firewall. The public option and the
NFS URL can be specified independently or together. They interact as specified in the following matrix:
4 Hewlett-Packard Company − 4 − HP-UX 11i Version 3: September 2010