(net-fs/nfs-utils-1.2.3-r1, 2.6.38.5-zen+ Gentoo)
Googling this seems to be a complete dead end. man nfsstat says a whole lot of nothing about the subject. The closest I could get was finding out about what was probably previously "newcreds".
newcreds
Number of times authentication information had to be refreshed.
My problem is that I think I'm seeing subpar NFS performance over OpenVPN and the only thing I can immediately see that is significantly different than all nfsstat Google results, is that my "calls" field equals exactly "authrefrsh" and is therefore very high. All the search result outputs always had authrefrsh as 0 or a very low number. Before I can move on to debugging some other aspects, I could use finding out what this means.
Watched operation is emerging a package over NFS-shared portage. emerge does traverse a big tree during it's operation but previous experience says the performance I'm seeing is abnormal.
$ watch -n 1 nfsstat -c
Every 1,0s: nfsstat -c Sat May 21 23:04:55 2011
Client rpc stats:
calls retrans authrefrsh
308565 2211 308565
Client nfs v3:
null getattr setattr lookup access readlink
0 0% 172372 55% 17 0% 30485 9% 36057 11% 26831 8%
read write create mkdir symlink mknod
25879 8% 107 0% 21 0% 0 0% 0 0% 0 0%
remove rmdir rename link readdir readdirplus
16 0% 0 0% 11 0% 0 0% 0 0% 16668 5%
fsstat fsinfo pathconf commit
3 0% 50 0% 25 0% 2 0%
I can't figure out exactly what authrefrsh is (and this spelling, is that intentional btw?) and why is it increasing like this in my case?
Best Answer
From the Red Hat article in the comments the solution says
Not very helpful but it also points out the reason it happens.
It references commit a17c2153d2e271b0cbacae9bed83b0eaa41db7e1 in the sunrpc package that moves where nfs authentication takes place. I won't copy/paste the entire commit but it mostly changes these lines.
My limited understanding is that this line moves where the call_refresh() happens (sooner rather than later). This in turn means most all nfs requests will cause authrefrsh to increment as authentication is always used.