How do I restart NFS server when network link goes down between two servers or NFS client / server under CentOS 4.x / RHEL / CentOS Linux 5.x?
The simplest and easiest way to stop and start (do not use restart option) NFS server under RHEL / CentOS / Fedora / Red Hat Linux is to use the init script located at /etc/init.d/ directory. Forceful umount command may result into more problems such as unresponsive NFS server and cold reboot may only solves the problem.
Stop and Start NFS and Related Services
For example type the following command to stop NFS server:
# service nfslock stop
# service nfs stop
# service portmap stop
# umount /proc/fs/nfsd
Now start service in following order:
# service portmap start
# service nfs start
# service nfslock start
# mount -t nfsd nfsd /proc/fs/nfsd