0b17c7bea5
we will only trust a positive name cache entry for a specified amount of time before falling back to a LOOKUP RPC, even if the ctime for the file handle matches the cached copy in the name cache entry. The timeout is configured via a new 'nametimeo' mount option and defaults to 60 seconds. It may be set to zero to disable positive name caching entirely. Reviewed by: rmacklem MFC after: 1 week
439 lines
14 KiB
Groff
439 lines
14 KiB
Groff
.\" Copyright (c) 1992, 1993, 1994, 1995
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 4. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" @(#)mount_nfs.8 8.3 (Berkeley) 3/29/95
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd May 3, 2011
|
|
.Dt MOUNT_NFS 8
|
|
.Os
|
|
.Sh NAME
|
|
.Nm mount_nfs
|
|
.Nd mount NFS file systems
|
|
.Sh SYNOPSIS
|
|
.Nm
|
|
.Op Fl 23bcdiLlNPsTU
|
|
.Op Fl a Ar maxreadahead
|
|
.Op Fl D Ar deadthresh
|
|
.Op Fl g Ar maxgroups
|
|
.Op Fl I Ar readdirsize
|
|
.Op Fl o Ar options
|
|
.Op Fl R Ar retrycnt
|
|
.Op Fl r Ar readsize
|
|
.Op Fl t Ar timeout
|
|
.Op Fl w Ar writesize
|
|
.Op Fl x Ar retrans
|
|
.Ar rhost : Ns Ar path node
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Nm
|
|
utility calls the
|
|
.Xr nmount 2
|
|
system call to prepare and graft a remote NFS file system
|
|
.Pq Ar rhost : Ns Ar path
|
|
on to the file system tree at the point
|
|
.Ar node .
|
|
This command is normally executed by
|
|
.Xr mount 8 .
|
|
It implements the mount protocol as described in RFC 1094, Appendix A and
|
|
.%T "NFS: Network File System Version 3 Protocol Specification" ,
|
|
Appendix I.
|
|
.Pp
|
|
If the file system type is specified as ``oldnfs'', which implies this
|
|
command is run as ``mount_oldnfs'', then it forces use of the old NFS
|
|
client, which does not support the
|
|
.Cm nfsv4
|
|
option.
|
|
.Pp
|
|
By default,
|
|
.Nm
|
|
keeps retrying until the mount succeeds.
|
|
This behaviour is intended for file systems listed in
|
|
.Xr fstab 5
|
|
that are critical to the boot process.
|
|
For non-critical file systems, the
|
|
.Cm bg
|
|
and
|
|
.Cm retrycnt
|
|
options provide mechanisms to prevent the boot process from hanging
|
|
if the server is unavailable.
|
|
.Pp
|
|
If the server becomes unresponsive while an NFS file system is
|
|
mounted, any new or outstanding file operations on that file system
|
|
will hang uninterruptibly until the server comes back.
|
|
To modify this default behaviour, see the
|
|
.Cm intr
|
|
and
|
|
.Cm soft
|
|
options.
|
|
.Pp
|
|
The options are:
|
|
.Bl -tag -width indent
|
|
.It Fl o
|
|
Options are specified with a
|
|
.Fl o
|
|
flag followed by a comma separated string of options.
|
|
See the
|
|
.Xr mount 8
|
|
man page for possible options and their meanings.
|
|
The following NFS specific options are also available:
|
|
.Bl -tag -width indent
|
|
.It Cm acregmin Ns = Ns Aq Ar seconds
|
|
.It Cm acregmax Ns = Ns Aq Ar seconds
|
|
.It Cm acdirmin Ns = Ns Aq Ar seconds
|
|
.It Cm acdirmax Ns = Ns Aq Ar seconds
|
|
When attributes of files are cached, a timeout calculated to determine
|
|
whether a given cache entry has expired.
|
|
These four values determine the upper and lower bounds of the timeouts for
|
|
.Dq directory
|
|
attributes and
|
|
.Dq regular
|
|
(ie: everything else).
|
|
The default values are 3 -> 60 seconds
|
|
for regular files, and 30 -> 60 seconds for directories.
|
|
The algorithm to calculate the timeout is based on the age of the file.
|
|
The older the file,
|
|
the longer the cache is considered valid, subject to the limits above.
|
|
.It Cm bg
|
|
If an initial attempt to contact the server fails, fork off a child to keep
|
|
trying the mount in the background.
|
|
Useful for
|
|
.Xr fstab 5 ,
|
|
where the file system mount is not critical to multiuser operation.
|
|
.It Cm deadthresh Ns = Ns Aq Ar value
|
|
Set the
|
|
.Dq "dead server threshold"
|
|
to the specified number of round trip timeout intervals before a
|
|
.Dq "server not responding"
|
|
message is displayed.
|
|
.It Cm dumbtimer
|
|
Turn off the dynamic retransmit timeout estimator.
|
|
This may be useful for UDP mounts that exhibit high retry rates,
|
|
since it is possible that the dynamically estimated timeout interval is too
|
|
short.
|
|
.It Cm fg
|
|
Same as not specifying
|
|
.Cm bg .
|
|
.It Cm hard
|
|
Same as not specifying
|
|
.Cm soft .
|
|
.It Cm intr
|
|
Make the mount interruptible, which implies that file system calls that
|
|
are delayed due to an unresponsive server will fail with EINTR when a
|
|
termination signal is posted for the process.
|
|
.It Cm maxgroups Ns = Ns Aq Ar value
|
|
Set the maximum size of the group list for the credentials to the
|
|
specified value.
|
|
This should be used for mounts on old servers that cannot handle a
|
|
group list size of 16, as specified in RFC 1057.
|
|
Try 8, if users in a lot of groups cannot get response from the mount
|
|
point.
|
|
.It Cm mntudp
|
|
Force the mount protocol to use UDP transport, even for TCP NFS mounts.
|
|
(Necessary for some old
|
|
.Bx
|
|
servers.)
|
|
.It Cm nametimeo Ns = Ns Aq Ar value
|
|
Override the default of NFS_DEFAULT_NAMETIMEO for the timeout (in seconds)
|
|
for positive name cache entries.
|
|
If this is set to 0 it disables positive name caching for the mount point.
|
|
.It Cm negnametimeo Ns = Ns Aq Ar value
|
|
Override the default of NFS_DEFAULT_NEGNAMETIMEO for the timeout (in seconds)
|
|
for negative name cache entries. If this is set to 0 it disables negative
|
|
name caching for the mount point.
|
|
.It Cm nfsv2
|
|
Use the NFS Version 2 protocol (the default is to try version 3 first
|
|
then version 2).
|
|
Note that NFS version 2 has a file size limit of 2 gigabytes.
|
|
.It Cm nfsv3
|
|
Use the NFS Version 3 protocol.
|
|
.It Cm nfsv4
|
|
Use the NFS Version 4 protocol.
|
|
This option will force the mount to use
|
|
TCP transport.
|
|
.It Cm noconn
|
|
For UDP mount points, do not do a
|
|
.Xr connect 2 .
|
|
This must be used if the server does not reply to requests from the standard
|
|
NFS port number 2049 or replies to requests using a different IP address
|
|
(which can occur if the server is multi-homed).
|
|
Setting the
|
|
.Va vfs.nfs.nfs_ip_paranoia
|
|
sysctl to 0 will make this option the default.
|
|
.It Cm nocto
|
|
Normally, NFS clients maintain the close-to-open cache coherency.
|
|
This works by flushing at close time and checking at open time.
|
|
Checking at open time is implemented by getting attributes from
|
|
the server and purging the data cache if they do not match
|
|
attributes cached by the client.
|
|
.Pp
|
|
This option disables checking at open time.
|
|
It may improve performance for read-only mounts,
|
|
but should only be used if the data on the server changes rarely.
|
|
Be sure to understand the consequences before enabling this option.
|
|
.It Cm noinet4 , noinet6
|
|
Disables
|
|
.Dv AF_INET
|
|
or
|
|
.Dv AF_INET6
|
|
connections.
|
|
Useful for hosts that have
|
|
both an A record and an AAAA record for the same name.
|
|
.It Cm nolockd
|
|
Do
|
|
.Em not
|
|
forward
|
|
.Xr fcntl 2
|
|
locks over the wire.
|
|
All locks will be local and not seen by the server
|
|
and likewise not seen by other NFS clients.
|
|
This removes the need to run the
|
|
.Xr rpcbind 8
|
|
service and the
|
|
.Xr rpc.statd 8
|
|
and
|
|
.Xr rpc.lockd 8
|
|
servers on the client.
|
|
Note that this option will only be honored when performing the
|
|
initial mount, it will be silently ignored if used while updating
|
|
the mount options.
|
|
.It Cm principal
|
|
For the RPCSEC_GSS security flavors, such as krb5, krb5i and krb5p,
|
|
this option sets the name of the host based principal name expected
|
|
by the server. This option overrides the default, which will be
|
|
``nfs@<server-fqdn>'' and should normally be sufficient.
|
|
.It Cm noresvport
|
|
Do
|
|
.Em not
|
|
use a reserved socket port number (see below).
|
|
.It Cm port Ns = Ns Aq Ar port_number
|
|
Use specified port number for NFS requests.
|
|
The default is to query the portmapper for the NFS port.
|
|
.It Cm rdirplus
|
|
Used with NFSV3 to specify that the \fBReaddirPlus\fR RPC should
|
|
be used.
|
|
For NFSV4, setting this option has a similar effect, in that it will make
|
|
the Readdir Operation get more attributes.
|
|
This option reduces RPC traffic for cases such as
|
|
.Dq "ls -l" ,
|
|
but tends to flood the attribute and name caches with prefetched entries.
|
|
Try this option and see whether performance improves or degrades.
|
|
Probably
|
|
most useful for client to server network interconnects with a large bandwidth
|
|
times delay product.
|
|
.It Cm readahead Ns = Ns Aq Ar value
|
|
Set the read-ahead count to the specified value.
|
|
This may be in the range of 0 - 4, and determines how many blocks
|
|
will be read ahead when a large file is being read sequentially.
|
|
Trying a value greater than 1 for this is suggested for
|
|
mounts with a large bandwidth * delay product.
|
|
.It Cm readdirsize Ns = Ns Aq Ar value
|
|
Set the readdir read size to the specified value.
|
|
The value should normally
|
|
be a multiple of
|
|
.Dv DIRBLKSIZ
|
|
that is <= the read size for the mount.
|
|
.It Cm resvport
|
|
Use a reserved socket port number.
|
|
This flag is obsolete, and only retained for compatibility reasons.
|
|
Reserved port numbers are used by default now.
|
|
(For the rare case where the client has a trusted root account
|
|
but untrustworthy users and the network cables are in secure areas this does
|
|
help, but for normal desktop clients this does not apply.)
|
|
.It Cm retrans Ns = Ns Aq Ar value
|
|
Set the retransmit timeout count for soft mounts to the specified value.
|
|
.It Cm retrycnt Ns = Ns Aq Ar count
|
|
Set the mount retry count to the specified value.
|
|
The default is a retry count of zero, which means to keep retrying
|
|
forever.
|
|
There is a 60 second delay between each attempt.
|
|
.It Cm rsize Ns = Ns Aq Ar value
|
|
Set the read data size to the specified value.
|
|
It should normally be a power of 2 greater than or equal to 1024.
|
|
This should be used for UDP mounts when the
|
|
.Dq "fragments dropped due to timeout"
|
|
value is getting large while actively using a mount point.
|
|
(Use
|
|
.Xr netstat 1
|
|
with the
|
|
.Fl s
|
|
option to see what the
|
|
.Dq "fragments dropped due to timeout"
|
|
value is.)
|
|
.It Cm sec Ns = Ns Aq Ar flavor
|
|
This option specifies what security flavor should be used for the mount.
|
|
Currently, they are:
|
|
.Bd -literal
|
|
krb5 - Use KerberosV authentication
|
|
krb5i - Use KerberosV authentication and
|
|
apply integrity checksums to RPCs
|
|
krb5p - Use KerberosV authentication and
|
|
encrypt the RPC data
|
|
sys - The default AUTH_SYS, which uses a
|
|
uid + gid list authenticator
|
|
.Ed
|
|
.It Cm soft
|
|
A soft mount, which implies that file system calls will fail
|
|
after
|
|
.Ar retrycnt
|
|
round trip timeout intervals.
|
|
.It Cm tcp
|
|
Use TCP transport.
|
|
This is the default option, as it provides for increased reliability on both
|
|
LAN and WAN configurations compared to UDP.
|
|
Some old NFS servers do not support this method; UDP mounts may be required
|
|
for interoperability.
|
|
.It Cm timeout Ns = Ns Aq Ar value
|
|
Set the initial retransmit timeout to the specified value.
|
|
May be useful for fine tuning UDP mounts over internetworks
|
|
with high packet loss rates or an overloaded server.
|
|
Try increasing the interval if
|
|
.Xr nfsstat 1
|
|
shows high retransmit rates while the file system is active or reducing the
|
|
value if there is a low retransmit rate but long response delay observed.
|
|
(Normally, the
|
|
.Cm dumbtimer
|
|
option should be specified when using this option to manually
|
|
tune the timeout
|
|
interval.)
|
|
.It Cm udp
|
|
Use UDP transport.
|
|
.It Cm wcommitsize Ns = Ns Aq Ar value
|
|
Set the maximum pending write commit size to the specified value.
|
|
This determines the maximum amount of pending write data that the NFS
|
|
client is willing to cache for each file.
|
|
.It Cm wsize Ns = Ns Aq Ar value
|
|
Set the write data size to the specified value.
|
|
Ditto the comments w.r.t.\& the
|
|
.Cm rsize
|
|
option, but using the
|
|
.Dq "fragments dropped due to timeout"
|
|
value on the server instead of the client.
|
|
Note that both the
|
|
.Cm rsize
|
|
and
|
|
.Cm wsize
|
|
options should only be used as a last ditch effort at improving performance
|
|
when mounting servers that do not support TCP mounts.
|
|
.El
|
|
.El
|
|
.Sh COMPATIBILITY
|
|
The following command line flags are equivalent to
|
|
.Fl o
|
|
named options and are supported for compatibility with older
|
|
installations.
|
|
.Bl -tag -width indent
|
|
.It Fl 2
|
|
Same as
|
|
.Fl o Cm nfsv2
|
|
.It Fl 3
|
|
Same as
|
|
.Fl o Cm nfsv3
|
|
.It Fl D
|
|
Same as
|
|
.Fl o Cm deadthresh
|
|
.It Fl I
|
|
Same as
|
|
.Fl o Cm readdirsize Ns = Ns Aq Ar value
|
|
.It Fl L
|
|
Same as
|
|
.Fl o Cm nolockd
|
|
.It Fl N
|
|
Same as
|
|
.Fl o Cm noresvport
|
|
.It Fl P
|
|
Use a reserved socket port number.
|
|
This flag is obsolete, and only retained for compatibility reasons.
|
|
(For the rare case where the client has a trusted root account
|
|
but untrustworthy users and the network cables are in secure areas this does
|
|
help, but for normal desktop clients this does not apply.)
|
|
.It Fl R
|
|
Same as
|
|
.Fl o Cm retrycnt Ns = Ns Aq Ar value
|
|
.It Fl T
|
|
Same as
|
|
.Fl o Cm tcp
|
|
.It Fl U
|
|
Same as
|
|
.Fl o Cm mntudp
|
|
.It Fl a
|
|
Same as
|
|
.Fl o Cm readahead Ns = Ns Aq Ar value
|
|
.It Fl b
|
|
Same as
|
|
.Fl o Cm bg
|
|
.It Fl c
|
|
Same as
|
|
.Fl o Cm noconn
|
|
.It Fl d
|
|
Same as
|
|
.Fl o Cm dumbtimer
|
|
.It Fl g
|
|
Same as
|
|
.Fl o Cm maxgroups
|
|
.It Fl i
|
|
Same as
|
|
.Fl o Cm intr
|
|
.It Fl l
|
|
Same as
|
|
.Fl o Cm rdirplus
|
|
.It Fl r
|
|
Same as
|
|
.Fl o Cm rsize Ns = Ns Aq Ar value
|
|
.It Fl s
|
|
Same as
|
|
.Fl o Cm soft
|
|
.It Fl t
|
|
Same as
|
|
.Fl o Cm retransmit Ns = Ns Aq Ar value
|
|
.It Fl w
|
|
Same as
|
|
.Fl o Cm wsize Ns = Ns Aq Ar value
|
|
.It Fl x
|
|
Same as
|
|
.Fl o Cm retrans Ns = Ns Aq Ar value
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr nmount 2 ,
|
|
.Xr unmount 2 ,
|
|
.Xr nfsv4 4 ,
|
|
.Xr fstab 5 ,
|
|
.Xr gssd 8 ,
|
|
.Xr mount 8 ,
|
|
.Xr nfsd 8 ,
|
|
.Xr nfsiod 8 ,
|
|
.Xr showmount 8
|
|
.Sh BUGS
|
|
Since nfsv4 performs open/lock operations that have their ordering strictly
|
|
enforced by the server, the options
|
|
.Cm intr
|
|
and
|
|
.Cm soft
|
|
cannot be safely used.
|
|
.Cm hard
|
|
nfsv4 mounts are strongly recommended.
|