General troubleshooting recommendations

From Linux NFS

I need to get detailed debug output of the client/server interactions

Start `tcpdump -s 9000 -w /tmp/dump.out port 2049` on the client, then conduct the client/server interaction.

I need to "reboot" the NFSv4 server but don't want to shut down the machine

Just shut down rpc.nfsd and start it again.

I get different results when mounting via NFSv3 and NFSv4

Find a file that is differing between v3 and v4, and look at the output from the `stat` utility.

Or use `ls -lid --type-style=full-iso` and `ls -lid --time=ctime --time-style=full-iso` if you don't have stat.