.\" SCCSID: @(#)mount.8nfs	8.3	9/28/90.TH mount 8nfs.SH Namemount, umount \- mount and unmount a Network File System (NFS).SH Syntax.B "/etc/mount [ \-t nfs \-f \-r \-v ] [".I options .B ] .I device directory.PP.B /etc/umount [.B \-v ] .I directory.SH Description.NXR "mount command (NFS)".NXR "umount command (NFS)".NXR "NFS file system" .NXR "mountd daemon".NXR "file system"The.PN mountcommand allows you to mount a file system or directoryonto a directory.Once a file system or directory has been mounted,it is treated as a file system..PPThe argument.I device can have one of the following forms:.IP\fIhost:remote_name\fR.IP\fIremote_name@host\fR.PPThe.I remote_nameis the name of a file system or subtree of a file systemthat has been exported by\fIhost\fR.The file.I directorymust exist and must be a directory.It becomes the name of the newly mounted file system..PPGeneral users can mount file systems with certain restrictionsin addition to those listed in .MS mount 8 ..PPThe.PN umountcommand unmounts the remote file system that was previouslymounted on the specified directory..SH OptionsSee the.MS mount 8reference page for a description of the \fB\-t\fR option..NXR "mount command (NFS)" "options".IP \fB\-f\fR 12Fast unmount.The.B \-foption has no meaning for local file systems and directories.However,for remote file system types (such as NFS), the.B \-foption causes the client to unmount the remotely mounted file systemsand directories without notifying the server.This can avoid the delay of waiting for acknowledgmentfrom a server that is down..IP \fB\-r\fR 12Indicates that the file systemis to be mounted read only..IP \fB\-v\fRTells what did or did not happen.(Verbose flag).IP "\fB\-o \fIoptions\fR"Specifies .I optionsas a sequence of words, separated by commas,from the list that follows. The default options are as follows:.sp .5\fBrw,hard,intr,retry=10,000,timeo=11,retrans=4, \\.brport=NFS_PORT,pgthresh=64\fR.sp .5Defaults for .I rsize and .I wsize are set by the kernel.The NFS options are as follows:.RS.PP.IP \fBbg\fR 14If the first mount attempt fails,retry the mount in the background the number of times specified(the default is 10,000 times)..IP \fBhard\fRRetry the NFS operation (not the \f(CWmount\fR)request until server responds.The.B hardoption applies after the.PN mounthas succeeded. Use the .B hard option when mounting .PN rw(read-write) file systems..IP \fBintr\fRAllow .B hard mounted file system operations to be interrupted..IP \fBnintr\fRDisallow .B hard mounted file system operations from being interrupted..IP \fBnoexec\fRBinaries cannot be executed from this file system..IP \fBnosuid\fRThe.PN setuidand.PN setgidprograms can not be executed from this file system..IP \fBpgthresh=##\fRSet the paging threshold for this file system in kilobytes..IP \fBport=\fIn\fRSet server IP port number to .I n..IP \fBretrans=\fIn\fR Set number of NFS operation retransmissions (not the \f(CWmount\fR) to .I n.The.B retrans=option applies after the.PN mounthas succeeded..IP \fBretry=\fIn\fRSet number of mount failure retries to .I n.The.B retry=option applies to the.PN mountcommand, itself..IP \fBro\fRRead-only..IP \fBrsize=\fIn\fRSet read buffer size to .I n bytes..IP \fBrw\fRRead/write..IP \fBsoft\fRReturn an error if the server does not respond to the NFS operation(not the \f(CWmount\fR)request.The.B softoption applies after the.PN mounthas succeeded.Do not use the .B softoption to mount.PN rw(read-write) file systems..IP \fBtimeo=\fIn\fRSet NFS timeout to .I n tenths of a second..IP \fBwsize=\fIn\fRSet write buffer size to .I nbytes..PP The following options affect how quickly you see updates to a file ordirectory that has been modified by another host.  Increasing these values will give you slightly better performance.  Decreasing these values decreases the time it takes for you to see modifications made on another host.If you arethe only modifier of files under this mount point, you can increasethese values..IP \fBacdirmin=\fIn\fR 14Hold cached directory attributes for at least \fIn\fR seconds.The default is 30 seconds..IP \fBacdirmax=\fIn\fR 14Hold cached directory attributes for no more than \fIn\fR seconds.The default is 60 seconds.  The maximum value allowed is 3600..IP \fBacregmin=\fIn\fR 14Hold cached file attributes for at least \fIn\fR seconds.  Thedefault is 3 seconds..IP \fBacregmax=\fIn\fR 14Hold cached file attributes for no more than \fIn\fR seconds.The default is 60 seconds.  The maximum value allowed is 3600..IP \fBactimeo=\fIn\fR 14Set all four attributes cache timeout values to \fIn\fR..IP \fBnoac\fR 14Do not set attribute caching.  This is equivalent to \fBactimeo=0\fR..RE.PPThe.PN bgoption causes .PN mountto run in the background if the server's.PN mountddaemon does not respond.  The.PN mount command attempts each request \fBretry=\fIn\fRtimes before giving up.Once the file system is mounted,each NFS request made in the kernel waits\fBtimeo=\fIn\fRtenths of a second for a response.If no response arrives,the time-out is multiplied by 2 and the request is retransmitted..PPWhen \fBretrans=\fIn\fRretransmissions have been sent with no reply, a.B softmounted file system returns an error on the request and a.B hardmounted file system retries the request.If a .B hard mounted file system was mounted with the.PN introption,an operation within that file system that is retrying(for example, the server is down) can be interrupted.File systems that are mounted .PN rw(read-write)should use the .B hardoption.The number of bytes in a read or write request can be set with the.PN rsizeand.PN wsizeoptions. The values for .PN rsizeand.PN wsizemust be between 512 and 8192, and be a multiple of 512..PPThe option for.PN umountis:.IP \fB\-v\fRTells what did or did not happen.(Verbose flag).SH Restrictions.NXR "mount command (NFS)" "restricted"If the directory on which a file system is to be mounted is asymbolic 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..PPThe.PN /etc/nfs_mountand.PN /etc/nfs_umountcommands should only be invoked by the.PN mountand.PN umountcommands.It is recommended that users (and superusers) do not invoke the.PN nfs_mountand.PN nfs_umountcommands. An exception to this rule is the use of the .PN nfs_umount .B \-b command in the.PN /etc/rc.local file. The .PN nfs_umount .B \-b command broadcasts a message informing NFS servers that this machineno longer has any NFS filesystems mounted. This is done in case themachine had crashed while it had NFS filesystems mounted. The serversuse this information to clean up their.PN rmtab tables. The.PN nfssetup command automatically adds the.PN nfs_umount.B \-bline to the.PN /etc/rc.local file on NFS client systems..SH Examples.NXR "mount command (NFS)".\" The.\" .PN nfs_mount.\" is not the suggested interface.The.PN mountcommand invokes.PN nfs_mountto do its work.A sample.PN mountcommand is:.IP "" 5# \fBmount \-t nfs \-o hard,pgthresh=100 server:/usr /usr\fR.\" This would be translated to \fBnfs_mount\fP as:.\" .EX 0.\" nfs_mount \-o hard,pgthresh=100 server:/usr /usr.\" .EE.PPTo mount the remote file system.PN /usr/srconto the local directory.PN /mntwith 1k transfer size,type:.IP "" 5# \fBmount \-t nfs \-o rsize=1024,wsize=1024 serv:/usr/src /mnt\fR.PPTo mount the remote directory.PN /usr/src/codeonto the local directory.PN /usr/src ,type:.IP "" 5# \fBmount \-t nfs serv:/usr/src/code /usr/src\fR.PPTo .B hard mount a remote file system called.PN /usr/srconto the local directory.PN /usr/src ,type:.IP "" 5# \fBmount \-t nfs \-o hard serv:/usr/src /usr/src\fR.\" The.\" .PN nfs_umount.\" is not the suggested interface..\" The .\" .PN umount .\" command invokes.\" .PN nfs_umount.\" to do its work..SH Files.TP 20.PN /etc/fstabFile system information file.TP.PN /etc/nfs_mountNFS-specific mount program.TP.PN /etc/nfs_umountNFS-specific unmount program.SH See Alsogetmnt(2), mount(2), fstab(5), exports(5nfs), mount(8),umount(8), mountd(8nfs), rmtab(5nfs), nfssetup(8nfs)