[Nottingham] NFSv3 - NFSv4 upgrade gotcha

[Camilo Mesias]

I thought I would upgrade my server and try out NFS4 this weekend, and
I found a few more gotchas.

My use case was "As a home user I want to share my photo archive onto
my desktop machines so I can index them with Picasa"

At first I found there were problems with using NFS4 through my
wireless network - it was doing NAT at the access point so I changed
that.

The NAT was messing up the identification of hosts which wouldn't
match the configurations in /etc/hosts

Another big gotcha was that so much of NFS (3 and 4) seems to have
moved into the kernel. Because of this, I think, reliable tools like
tcpdump were not showing expected traffic arriving at the server.
Error messages would appear in the logs and rpcinfo would show that
comms was up but no packets were seen with my tcpdump. This was really
confusing and broke my age-old ground up debugging assumptions.

Finally I gave up with NFS4 when it seemed like I would need a
Kerberos security infrastructure - ideally, running on a separate
dedicated machine. This is way OTT for my home network. I backed out
to NFSv3 (the only change to make this work on my network was to
remove NAT from the AP).

-Cam