I'm learning for the LPIC exam which includes a section about Samba. I'm asking myself, whether there is any meaningful or useful application for Samba in a pure Unix/Linux network without any Windows clients or servers?
CIFS/Samba and NFS are profoundly different protocols with different implementations. Of course there may be reasons to prefer CIFS over NFS in certain scenarios, sometimes even out of performance considerations (CIFS offers more intelligent caching support through the use of oplocks whereas NFS lacks such a mechanism). The reasons for preferring Samba over the NFS implementation in a pure Linux environment obviously would need to be carefully weighted, but may be valid nonetheless.
For the general use, I would quote from the conclusion of a paper by one of the Samba team members, which also offers a lot of information comparing these two protocols:
With current Linux kernels, NFS version 4 and CIFS (cifs client/Samba server) are good choices for network file systems for Linux to Linux. NFS performance for large file copy workloads is better, and NFS offers some security options that the Linux cifs client does not. In heterogeneous environments that include Windows clients and servers, Samba is often much easier to configure.
in a pure Unix/Linux network without any Windows clients or servers?
Be carefull that this is true - and stays so.
As in: No people coming from outside with laptops, no small devices that can deal with a windows share but not anything else. Example? I recently installed a computer. I COULD have mounted the ISO file in the KVM from a windows share, but not from anything else - so I did use the mapping from my browser via Java remotely, but just to make the point: a lot of stuff supports windows style file shares, and you can be "all linux" as you want, when you call your supplier and get them reprogram a firmware you do not look smart.
Then there are external people that may come in and have Windows installed.