Tuesday, August 28, 2007

NFS advanced mount options

Taken from http://uw714doc.sco.com/en/FS_manager/nfsD.nfsopt.html
Many thanks to Suhaila

NFS advanced mount options

The Filesystem Manager supports the following mount options for NFS filesystems:

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

This is recommended for automatic mounts done during system startup. The default is to mount in the foreground.

This is recommended if you wish to see whether the mount was successful.

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

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.

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.

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.

Allow Keyboard Interrupts
allows keyboard interrupts on hard mounts.

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.

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.

Cache attributes

caches the file attributes. This eliminates redundant requests to the server for file information/attributes. This option is the default.

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
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.

Alternate IP Port Number
set the server IP port number (the default port number is 2049).

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