All,

I am trying to conduct a few performance tests to determine which block size is best suited for my NFS server/client connections. I can't seem to find where the default block size is defined at. Can you help me? I am using kernel 5.8 Fedora 32 with NFS V4.

Thanks

Sal

NFS does not really have a "best block size". NFS depends upon the speed of the native file system on the host, and transports in network "packets". It is a Network File System and you really cannot treat it (except at the most trivial level) like a physical file system.

To tune NFS performance you need to have a physical file system that is not a bottleneck, and tune TCP. Network is virtually ALWAYS slower than rotational storage anyway. If your connection is direct, expanding packet size is perfect. If you go through network devices that do not support it, you need to examine the MTU of each connection and chose the largest packet size that will avoid fragmentation in transit. If that makes no sense to you, you are probably better off leaving things alone. (Untrained, you are more likely to make things worse than better.)