Lesson 5

Date: 2/19/2009
Network File System (NFS)
Linux for Engineering and IT Applications


NFSv3 daemons
  • NFS registers its processes (RPC services) with portmap.
  • The portmap holds the port, service number and version numbers for each RPC service. If the portmap goes down, then all services need to be restarted after the portmap is restarted.

  • NFS server daemons
    portmap handles RPC requests and registers ports for RPC services
    rpc.mountd handles the initial mount requests
    nfsd or [nfsd] handles data streaming
    rpc.rquotad handles user file quotas on exported volumes
    [lockd] handles file locking to make sure several processes don't write into the same file
    rpc.statd lock monitor daemon works with [lockd]
    Note, [nfsd] and [lockd] above mean they run by the Kernel threads and don't need to be started by a user.

  • NFS client daemons 
    portmap
[lockd]
rpc.statd

  • To verify that the services have started and registeresd with portmap, run command 
    rpcinfo -p


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