NAME

mount, umount − mount and unmount a Network File System (NFS)

SYNTAX

/etc/mount −t nfs [ −r −v −o options ] special name

/etc/umount [ −v ] name

DESCRIPTION

The mount(8nfs) command determines if the file system to be mounted is of type NFS.  The file system is of type NFS if the special argument is of the form: host:remote_name.  Remote_name is the name of a file system (or subtree of a file system) that has been exported by host.  The file name must exist and it must be a directory.  It becomes the name of the newly mounted file system. 

The umount(8nfs) command unmounts the remote file system that was previously mounted on directory name. 

OPTIONS

−r Indicates that the file system is to be mounted read-only. 

−v Verbose flag to tell what did or did not happen. 

−o options Specifies options as a sequence of comma-separated words from the list below.  The defaults are: rw,hard,intr,retry=10,000,timeo=11,retrans=4,port=NFS_PORT Defaults for rsize and wsize are set by the kernel.  The NFS options are:

rwread/write. 

roread-only. 

bgIf the first mount attempt fails, retry in the background. 

retry=nSet number of mount failure retries to n. 

rsize=nSet read buffer size to n bytes. 

wsize=nSet write buffer size to n bytes. 

timeo=nSet NFS timeout to n tenths of a second. 

retrans=nSet number of NFS retransmissions to n. 

port=nSet server IP port number to n. 

softReturn error if server doesn’t respond. 

hardRetry request until server responds. 

intrAllow hard mounted file system operations to be interrupted. 

nosuidSetuid and setgid programs may not be executed from this file system. 

noexecBinaries cannot be executed from this file system. 

pgthresh=##
Set the paging threshold for this file system in kilobytes.

The bg option causes mount to run in the background if the server’s mountd(8nfs) does not respond.  mount attempts each request retry=n times before giving up.  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 retrans=n retransmissions have been sent with no reply a soft mounted file system returns an error on the request and a hard mounted file system retries the request.  If a hard mounted file system was mounted with the intr option, an operation within that file system that is retrying (for example, the server is down) can be interrupted.  Filesystems that are mounted rw (read-write) should use the hard option.  The number of bytes in a read or write request can be set with the rsize and wsize options. 

The option for umount is:

−v Verbose output format to tell what did or did not happen. 

EXAMPLES

The mount(8nfs) command invokes nfs_mount to do its work.  A sample mount command is:

# mount −t nfs −o hard,pgthresh=100 server:/usr /usr

To mount with 1K transfer size:

# mount −t nfs −o soft,rsize=1024,wsize=1024 serv:/usr/src /usr/src

To mount a remote file system:

# mount −t nfs serv:/usr/src /usr/src

To hard mount a remote file system:

# mount −t nfs −o hard serv:/usr/src /usr/src

RESTRICTIONS

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. 

The /etc/nfs_mount and /etc/nfs_umount commands should only be invoked by the mount(8nfs) and umount(8nfs) commands.  Users (and superusers) should not invoke the nfs_mount and nfs_umount commands. 

FILES

/etc/fstabFile system information file.  /etc/nfs_mount NFS specific mount program.  /etc/nfs_umount NFS specific unmount program. 

SEE ALSO

getmnt(2), mount(2), fstab(5), exports(5nfs), mount(8), umount(8), mountd(8nfs)