mount: unknown filesystem type 'nfsd'

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Environment

SUSE Linux Enterprise Server 12 (any support pack)

Situation

During attempts to start nfsserver (such as "systemctl start nfsserver") or other nfs-related services, the following error is seen (amongst various other errors):

mount[xxxx]: mount: unknown filesystem type 'nfsd'

Note that "nfsserver" or "nfs server" refers to a system which is sharing it's own native file systems via the nfs protocol. Other systems which mount those shares via nfs are referred to as "nfs clients".

Resolution

The above error means that the "nfsd" kernel module is missing. This normally will only occur if the full kernel is not installed. For example, some administrators have chosen to only install a minimal kernel, such as "kernel-default-base" rather than the full kernel package of "kernel-default".

The base package does not support nfsd (nfs server) functions. More than one component needed to be an nfs server is intentionally missing.

To resolve this, go into YaST --> Software Management and install the full kernel package. When selecting to do so, YaST should warn that this will cause a conflict and the base package must be removed. Allow it to do so.

While it might be possible to track down the various missing components and manually add them to the system in question, SUSE support and development will not support NFS Server functions on any system which is not using the full kernel package.

Additional Information

Note that mount type "nfsd" is a special mount type used by the nfsd (nfs server) kernel module. In contrast, nfs clients mount nfs shares with type "nfs" or sometimes "nfs4".

On an Linux nfs server machine that is running correctly, this special mount can be seen as follows:

# mount | grep nfsd
nfsd on /proc/fs/nfsd type nfsd (rw,relatime)

It will not appear in /etc/fstab. It is automatically mounted when the nfsserver service is started.

Disclaimer

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