Configuring the Network File System (NFS)

NFS filesystem advanced mount options

In the Filesystem Manager, select Add Mount Configuration or Modify Mount Configuration from the Filesystem menu, then select Remote. After you have selected a remote filesystem, select Advanced Options.

When mounting a remote filesystem, an NFS client can specify options that characterize the individual mount request. The following options can be set from the Filesystem Manager:

Mount in background

specifies that the NFS mount should be retried in the background if the server's mount daemon (mountd) does not respond.

Yes: This is recommended for automatic mounts done during system startup. The default is to mount in the foreground.
No: This is recommended if you wish to see whether the mount was successful.

NFS mount type

specifies how the client acts if the server does not respond to its NFS request.

Hard: retries indefinitely. The client will continue to attempt the NFS file operation indefinitely if the operation fails. Hard mounts should be used when the server and the link to the server are known to be reliable. Hard mounts with the interruptible option enabled is the recommended method of mounting remote filesystems. The default is hard mount.
Soft: retries NFS file operation n times as set by the number of retries before reporting error option; returns error if no server response in n tries. Soft mounts are recommended for filesystems whose servers are considered unreliable, or if the link is slow. Unlike spongy mounts, soft mounts may time out during read and write operations.
Spongy: sets soft semantics for stat, lookup, fsstat, readlink, and readdir NFS operations and hard semantics for all other NFS operations on the filesystem. Spongy mounts are preferable to soft mounts because spongy mounts will not time out during read and write operations. They are recommended for slow, long-distance, or unreliable links, and for unreliable servers.

Keyboard interruptible

allows keyboard interrupts on hard mounts.

Yes: allows the user to kill a process that is hung while waiting for a response on a hard-mounted filesystem. This option is useful if the server or the connection to the server is known to be slow or unreliable. It is recommended to always have the intr option on. A keyboard interrupt is configured by entering stty intr key where key is the keyboard key you wish to use to issue an interrupt.
No: specifies that the user cannot terminate an NFS operation from the keyboard. This should only be used if the server and link to the server are known to be reliable. Non-interruptible is the default.

SUID and SGID file permissions

controls SUID and SGID execution permissions for binaries in exported filesystems; for more information, see ``SUID/SGID bits and security'' and ``SUID, SGID, and sticky bit clearing on writes''.

Honor: accepts imported SUID and SGID execution permissions as they are set in the remote filesystem. This is the default.
Ignore: ignores imported SUID and SGID execution permissions. Use this option if you are concerned with filesystem security.

Cache attributes

Yes: caches the file attributes. This eliminates redundant requests to the server for file information/attributes. This option is the default.
No: does not cache attributes. Use this option when close synchronization with the server is required. Note that using this option will drastically impair performance on the filesystem being mounted.

Read/write buffer size (bytes)

specifies client read and write buffer sizes in bytes (the default size is 8192 bytes). This should be lowered if you have a slow Ethernet card.

Timeout period for each operation (seconds)

sets the initial NFS timeout for each RPC operation to n seconds. The default is 300 seconds.

Number of retries before reporting error

specifies (for soft mounts only) the number of NFS retransmissions the client will make before reporting an error. The default is 5.

The following option can be set when invoking NFS from /etc/nfs:

Transport protocol

sets the transport protocol for this filesystem

TCP: specifies the Transmission Control Protocol (TCP); this is recommended if reliable connections are required
UDP: specifies the User Datagram Protocol (UDP); this is the default