NAME | SYNOPSIS | DESCRIPTION | OPTIONS | ATTRIBUTES | SEE ALSO
mount_nfs is a target utility.
mount_nfs calls the mount(2POSIX) system call to prepare and graft a remote NFS file system (hostaddr:file_system) onto the file system tree at the mount_point. The command is normally executed by mount(1M). It implements the mount protocol as described in RFC 1094, Appendix A and , NFS: Network File System Version 3 Protocol Specification, Appendix I.
mount_nfs supports the following options:
Use the NFS Version 2 protocol (the default is to try version 3 first then version 2).
Use the NFS Version 3 protocol.
Set the read-ahead count to the specified value. This may be in the range of 0 to 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.
If an initial attempt to contact the server fails, fork off a child to keep trying the mount in the background. Useful when the filesystem mount is not critical to multiuser operation.
For UDP mount points, do not do a connect(2POSIX). This must be used for servers that do not reply to requests from the standard NFS port number 2049.
Used with NQNFS to set the dead server threshold to the specified number of round trip timeout intervals. After a dead server threshold of retransmit timeouts, cached data for the unresponsive server is assumed to still be valid. Values may be set in the range of 1 to 9, with 9 referring to an infinite dead threshold (never assume cached data is still valid). This option is not generally recommended and is really an experimental feature.
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.
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 many groups cannot get a response from the mount point.
Set the readdir read size to the specified value. The value should normally be a multiple of DIRBLKSIZ
that is less than or equal to the read size for the mount.
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.
Pass Kerberos authenticators to the server for client-to-server user-credential mapping. This requires that the kernel be built with the NFSKERB
option. (Refer to the INTERNET-DRAFT titled Authentication
Mechanisms for ONC RPC, for more information.)
Used with NQNFS
to set the lease term to the specified number of seconds. Only use this argument for mounts with a large round trip delay. Values are normally in the 10-30 second range.
Used with NQNFS and NFSV3 to specify that the ReaddirPlus RPC should be used. This option reduces RPC traffic for cases such as 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 * delay product.
Set the Kerberos realm to the string argument. Used with the -K option for mounts to other realms.
Options are specified with a -o flag followed by a comma separated string of options. See mount(1M) for possible op tions and their meanings. The following NFS specific option is also available:
Use specified port number for NFS requests. The default is to query the portmapper for the NFS port.
Historic options:
Same as -b.
Same as not specifying -c.
Same as -d.
Same as -i.
Same as -K.
Same as -2.
Same as -3.
Same as -l.
Same as -q.
Same as -s.
Use the leasing extensions to the NFS Version 3 protocol to maintain cache consistency. This protocol Version 2, referred to as Not Quite Nfs (NQNFS), is only supported by this updated release of NFS code. (It is not backwards compatible with the release of NQNFS that went out on 4.4BSD-Lite. To interoperate with a 4.4BSD-Lite NFS system you will have to avoid this option until you have had an opportunity to upgrade the NFS code on all your 4.4BSD-Lite based systems.)
Set the retry count for doing the mount to the specified value.
Set the read data size to the specified value. It should normally be a power of two greater than or equal to 1024. This should be used for UDP mounts when the fragments dropped due to timeout value is getting large while actively using a mount point. (Use netstat(1) with the -s option to see what the fragments dropped due to timeout value is.) See the -w option as well.
A soft mount, which implies that file system calls will fail after Retry round trip timeout intervals.
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 nfsstat(1CC) 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 -d option should be specified when using this option to manually tune the timeout interval.)
Set the write data size to the specified value. See the comments for the -r option, but considering the fragments dropped due to timeout value on the server instead of the client. Note that both the -r and -w options should only be used as a last ditch effort at improving performance when mounting servers that do not support TCP mounts.
Set the retransmit timeout count for soft mounts to the specified value.
See attributes(5) for descriptions of the following attributes:
ATTRIBUTE TYPE | ATTRIBUTE VALUE |
---|---|
Interface Stability | Evolving |
NAME | SYNOPSIS | DESCRIPTION | OPTIONS | ATTRIBUTES | SEE ALSO