mount(1M) (NFS) mount(1M)
NAME
mount - mount remote NFS resources
SYNOPSIS
mount [ -F nfs ] [ -r ] [ -o specific_options ] [ resource mountpoint
]
DESCRIPTION
The mount command attaches a named resource to the file system
hierarchy at the pathname location mountpoint, which must already
exist. If mountpoint has any contents prior to the mount operation,
the contents remain hidden until the resource is once again
unmounted.
If the resource is listed in the vfstab file, the command line can
specify either resource or mountpoint, and mount will consult vfstab
for more information. If the -F option is omitted, mount will take
the file system type from vfstab.
mount maintains a table of mounted file systems in /etc/mnttab,
described in mnttab(4).
The following options are available to the mount command:
-r Mount the specified file system read-only.
-o specific_options
Specify file system specific options in a comma-separated list
of words from the list below.
rw|ro resource is mounted read-write or read-only. The
default is rw.
nosuid Setuid execution allowed or disallowed. The
default is suid.
remount If a file system is mounted read-only, remounts
the file system read-write.
bg|fg If the first attempt fails, retry in the
background, or, in the foreground. The default
is fg.
retry=n The number of times to retry the mount operation.
The default is 10000.
port=n The server IP port number. The default is
NFSPORT.
grpid Create a file with its GID set to the effective
GID of the calling process. This behavior may be
overridden on a per-directory basis by setting
the set-GID bit of the parent directory; in this
case, the GID is set to the GID of the parent
directory [see open(2) and mkdir(2)]. Files
created on file systems that are not mounted with
the grpid option will obey BSD semantics; that
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is, the GID is unconditionally inherited from
that of the parent directory.
rsize=n Set the read buffer size to n bytes.
wsize=n Set the write buffer size to n bytes.
timeo=n Set the NFS timeout to n tenths of a second.
retrans=n Set the number of NFS retransmissions to n.
soft|hard Return an error if the server does not respond,
or continue the retry request until the server
responds.
intr Allow keyboard interrupts to kill a process that
is hung while waiting for a response on a hard-
mounted file system.
secure Use a more secure protocol for NFS transactions.
noac Suppress attribute caching.
acregmin=n Hold cached attributes for at least n seconds
after file modification.
acregmax=n Hold cached attributes for no more than n seconds
after file modification.
acdirmin=n Hold cached attributes for at least n seconds
after directory update.
acdirmax=n Hold cached attributes for no more than n seconds
after directory update.
actimeo=n Set min and max times for regular files and
directories to n seconds.
NFS FILE SYSTEMS
Background vs. Foreground
File systems mounted with the bg option indicate that mount is to
retry in the background if the server's mount daemon [mountd(1M)]
does not respond. 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.
Read-Write vs. Read-Only
File systems that are mounted rw (read-write) should use the hard
option.
Secure File Systems
The secure option must be given if the server requires secure
mounting for the file system.
File Attributes
The attribute cache retains file attributes on the client.
Attributes for a file are assigned a time to be flushed. If the file
is modified before the flush time, then the flush time is extended by
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the time since the last modification (under the assumption that files
that changed recently are likely to change soon). There is a minimum
and maximum flush time extension for regular files and for
directories. Setting actimeo=n extends flush time by n seconds for
both regular files and directories.
EXAMPLES
To mount a remote file system: mount -F nfs serv:/usr/src /usr/src
To hard mount a remote file system: mount -o hard serv:/usr/src
/usr/src
FILES
/etc/mnttab table of mounted file systems
/etc/dfs/fstypes default distributed file system type
/etc/vfstab table of automatically mounted resources
SEE ALSO
mountall(1M), mount(2), umount(2), mnttab(4).
NOTES
If the directory on which a file system is to be mounted is a
symbolic link, the file system is mounted on the directory to which
the symbolic link refers, rather than being mounted on top of the
symbolic link itself.
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