Friday, 2 November 2012

Difference between Soft Mount & Hard Mount


The directory /nfs   should be created in your node/server. The nfs mount can be mount as a “soft mount” or as a “hard mount” these mount option define the how the nfs client should be handle nfs crash/failure. We will see the difference between hard mount and soft mount.

Soft mount:- suppose you have mount the nfs by using “soft mount’ when a program request a file from nfs server. Nfs demon will try to retrieve the data from the nfs server. If doesn’t get any response from nfs server due to some failure or crash on nfs server. Then nfs client report an error to the process on the client machine requesting the file access the Advantage “fast responsiveness”   it doesn’t wait to the nfs server to respond. The Main Disadvantage of this method is data corruption or loss of data so this is not the recommended option to use.

 [root@sadeek ~]# showmount -e 172.28.50.109
Export list for 192.168.0.105:
/nfs *
Soft mounting (Temporary Mounting):-
[root@sadeek ~]# mount   172.28.50.109:/nfs/  /mnt/


Hard mounting:-if you have mounted the nfs by “hard mount”.  It will repeatly try to connect to the server. Once the server is back online the program will continue to execute undisturbed the state where it was during the crash. We can use the mount option “intr’ which allows nfs request to interrupt if the server goes down or cannot be access able.


Hard Mount (Permanent mounting):-
[root@sadeek~]# mount  -o rw,hard,intr  172.28.50.109/nfs  /mnt
[root@sadeek ~]# vim  /etc/fstab
172.28.50.109:/nfs       /mnt                         nfs    Defaults    0 0
:wq!
We can check nfs share  with the help of below mention command.
[root@sushee ~]# mount –a

2 comments:

  1. Thanks for the tutorial, want to know how data gets corrupted in soft mount.

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