What are the different NFS mounts ?

[Huber_5]

Hi all,

I've heard that there are several way of mounting NFS directories: some are hard ones, others are soft ones. What does this mean?
My problem is that my client is afraid about NFS because they have had experience of system panic with NFS, but it was probably this famous hard NFS mount. In that case, if there is any problem in the network, nfsd tries indefinitely to connect and the system hangs. That's why I'm looking for a NFS mount probably less reliable in terms of connectivity but safer for the system.

Thanks in advance for your help.

Anselme Huber

[Stefan Farrelly · Accepted solution]

You definitely want nfs soft mounting then. This is much safer as if the source of the nfs mount point is unavailable it wont severely impact the server its mounted on like a hard mount would.

mount options should be;
soft,retry=999

(so if the source does go down nfs will keep retrying to see if its back up)

[U.SivaKumar_2]

Hi,

ref:
This is a UNIX terminology as to what the client does when it can't talk to an NFS Server. If you just mount a file system without specifying hard or soft, the default is a hard mount. Hard mounts are preferable because of the stateless nature of NFS. If a client sends an I/O request to the server (such as an ls -la), and the server gets rebooted, the client will wait until the server comes back on line. This preserves data transfers in the event of a server failure. There are disadvantages to this, as a simple mount request could hang. A soft link will return with an error and fail. This kills the wait time, but can cause problems with data transfers.

Better is the soft mount for situation.

mount -o ro,soft nfserver:/home/data /data

regards ,
U.SivaKumar

[Huber_5]

Thank you all for your answers. It's very clear: I will use soft mount.