1)NFS daemon repeately contact the server.
2)if server is down,affect the performance. we can't interrupt them,
3)if nfs server is down, it will not umount the file system till user manually unmount file system.
Example : mount point entry in /etc/fstab is called hard mount. so while the client system boot up client will try to mount the from the server. if the server is up it client system will boot-up if the server is down the client system will not go ahead, the client system will hang.
Soft Mount Point : if the client unable to connect the server it will through the error message, it will not affect the booting process.
1)NFS repeatedly to contact server.
a)connection is established,
b)NFS retry threshold is met.
c)nfstimeout value is reached
2)If the server is down,just through error message, but not affect the system performance.
3)if the nfs server is down, it is automatically the umount the file system.Example: mount point entry located in /etc/auto.master and /etc/auto.misc .when the client system bootup it will try to mount the file from the server . if the server is up then it will mount or it will through the error message.