NFS Services Administrator's Guide

Configuring and Administering NFS
Configuring and Administering an NFS Client
Chapter 252
O (Overlay
mount)
default: not
specified
Allows the file system to be mounted over an
existing mount point, making the underlying file
system inaccessible. If you attempt to mount a file
system over an existing mount point without the
-O option, the mount will fail with the error
device busy.
Caution: Using the -O mount option can put your
system in a confusing state. The -O option allows
you to hide local data under an NFS mount point
without receiving any warning. Local data hidden
beneath an NFS mount point will not be backed
up during regular system backups.
On HP-UX, the -O option is valid only for
NFS-mounted file systems. For this reason, if you
specify the -O option, you must also specify the -F
nfs option to the mount command or the nfs file
system type in the /etc/fstab file.
proto=<transp> Allows user to specify which transport option
should be used: UDP or TCP. Once specified, NFS
only attempts to connect using that transport
option. If the specified transport option is not
available, the mount fails.
remount
default: not
specified
If the file system is mounted read-only, this option
remounts it read/write. This allows you to change
the access permissions from read-only to
read/write without forcing everyone to leave the
mounted directory or killing all processes using it.
grpid
default: not
specified
Forces a newly created file in the mounted file
system to inherit the group ID of the parent
directory.
By default, a newly created file inherits the
effective group ID of the calling process, unless
the GID bit is set on the parent directory. If the
GID bit is set, the new file inherits the group ID of
the parent directory.
Table 2-2 NFS Mount Options (Continued)