/usr/etc/umount -a [ v ]
/usr/etc/umount [ -v ] filesystem|directory ...
/usr/etc/umount [ -d ] RFS-resource | directory
mount attaches a named filesystem to the file system hierarchy at the pathname location directory, which must already exist. If directory has any contents prior to the mount operation, these remain hidden until the filesystem is once again unmounted. If filesystem is of the form host:pathname, it is assumed to be an NFS file system (type nfs).
umount unmounts a currently mounted file system, which can be specified either as a directory or a filesystem.
mount and umount maintain a table of mounted file systems in /etc/mtab, described in fstab.5 If invoked without an argument, mount displays the contents of this table. If invoked with either a filesystem or directory only, mount searches the file /etc/fstab for a matching entry, and mounts the file system indicated in that entry on the indicated directory.
mount also allows the creation of new, virtual file systems using loopback mounts. Loopback file systems provide access to existing files using alternate pathnames. Once a virtual file system is created, other file systems can be mounted within it without affecting the original file system. File systems that are subsequently mounted onto the original file system, however, are visible to the virtual file system, unless or until the corresponding mount point in the virtual file system is covered by a file system mounted there.
Recursive traversal of loopback mount points is not allowed; after the loopback mount of /tmp/newroot, the file /tmp/newroot/tmp/newroot does not contain yet another file system hierarchy. Rather, it appears just as /tmp/newroot did before the loopback mount was performed (say, as an empty directory).
The standard RC files first perform 4.2 mounts, then nfs mounts, during booting. On Sun386i systems, lo (loopback) mounts are performed just after 4.2 mounts. /etc/fstab files depending on alternate mount orders at boot time will fail to work as expected. Manual modification of /etc/rc.local will be needed to make such mount orders work.
See lofs.4s and fstab.5 for more information and WARNINGS about loopback mounts.
Physically write-protected and magnetic-tape file systems must be mounted read-only. Otherwise errors occur when the system attempts to update access times, even if no write operation is attempted.
options valid on all file systems:
The default is `rw,suid'.
options specific to 4.2 file systems:
options specific to nfs (NFS) file systems:
Regular defaults are:
actimeo has no default; it sets acregmin, acregmax, acdirmin and acdirmax
Defaults for rsize and wsize are set internally by the system kernel.
options specific to rfs (RFS) file systems:
Defaults are the same as for NFS.
options specific to hsfs (HSFS) file systems:
Filesystems mounted with the bg option indicate that mount is to retry in the background if the server's mount daemon (mountd(8C)) 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.
File systems that are mounted rw (read-write) should use the hard option.
option allows keyboard interrupts to kill a process that is hung
while waiting for a response on a hard-mounted file system.
Quota checking on NFS file systems is performed by the server, not the client; if the file system has the quota option on the server, quota checking is performed for both local requests and NFS requests. When a user logs in, login.1 runs the quota.1 program to check whether the user is over their quota on any of the file systems mounted on the machine. This check is performed for NFS file systems by an RPC call to the rquotad.8c server on the machine from which the file system is mounted. This can be time-consuming, especially if the remote machine is down. If the noquota option is specified for an NFS file system, quota will not check whether the user is over their quota on that file system, which can speed up the process of logging in. This does not disable quota checking for operations on that file system; it merely disables reporting whether the user is over quota on that file system.
The secure option must be given if the server requires secure mounting for the file system.
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 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.
Ordinarily, when a file is created its GID is 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.2v and mkdir.2v Files created on file systems that are mounted with the grpid option will obey BSD semantics; that is, the GID is unconditionally inherited from that of the parent directory.
Note: this is not recommended when running the automounter, see automount.8
mount -t lo /export/var/localhost /var lo mount -t lo /export/cluster/sun386.sunos4.0.1 /usr/cluster mount -t lo /export/local/sun386 /usr/local
mount does not understand the mount order dependencies involved in loopback mounting. Loopback mounts may be dependent on two mounts having been previously performed, while nfs and 4.2 mounts are dependent only on a single previous mount. As a rule of thumb, place loopback mounts at the end of the /etc/fstab file. See lofs.4s for a complete description.
Mounting file systems full of garbage crashes the system.
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.
Created by unroff & hp-tools. © by Hans-Peter Bischof. All Rights Reserved (1997).
Last modified 21/April/97