NFS Troubleshooting

This shows you how to troubleshoot NFS issues properly for debian-based systems

Mount errors

Error: Can't read superblock
In order to mount a NFS network file system, it is necessary to run the portmapper on the client computer. An error may occur, if an attempt is made to mount a NFS network file system without the local portmapper running:
  •  mount scooby:/foobar /nfs/scooby/foobar mount: scooby:/foobar Can't read superblock

mount.nfs: rpc.statd is not running but is required for remote locking :: This error occurs if the portmapper has not been started on the client machine.

NFSv4 Problems with uid/gid not synchronizing properly

Make sure that you have access to port 2049 from the client to the server (hint: telnet 2049). If no firewalls are blocking your traffic, then proceed to make sure that you add an "actimeo" option to your nfs client like the following:

Example: nfs client

$> cat /etc/auto.master
/mnt/auto       /etc/auto.nfs --timeout=60

$> cat /etc/auto.nfs
backup          -fstype=nfs4,rw,rsize=32768,wsize=32768,timeo=14,intr,actimeo=10,20,10,20

See man nfs for more on what "actimeo" means. server is configured using the following lines:

Example: nfs server

# /etc/exports: the access control list for filesystems which may be exported

#               to NFS clients.  See exports(5).

/mnt/shared            *,fsid=0,no_subtree_check,insecure,sync,crossmnt)
/mnt/shared/tmp        *,no_subtree_check,insecure,sync)