NFS Mount Causes ORA-27086: unable to lock file – already in use

The following error can occur with other errors if you have a database on NFS mount point:
ORA-27086: unable to lock file – already in use

To fix it, you can simply do the following as root user:

Check if 'nfslock' service is running:
# service nfslock status
rpc.statd is stopped

Start the 'nfslock' service:
# /etc/init.d/nfslock start
Starting NFS statd:                                        [  OK  ]

Check if 'nfslock' service is running:
# service nfslock status
rpc.statd (pid  XXXX) is running...

Ensure the 'nfslock' service start up automatically when the server reboots:
# chkconfig nfslock on

Once the 'nfslock' service is up and running, you should be able to start your database without those locking errors.