Re: FreeBSD 13.2 NFS client mount hangs

On Sat, Sep 30, 2023 at 6:06 PM Rick Macklem <rick.macklem@gmail.com> wrote:
> --> I'd suggest you try and disable delegations.  I do not know how to
> do this on
>      the Linux server, but not running the nfscbd(8) daemon should stop them
>      from being issued.

The nfscbd daemon is not running on any of the clients.

> If the Linux server still
> issues delegations

How would I determine that?

> Hmm, interesting. 10068 is NFS4ERR_RETRY_UNCACHED_REP.
> I have never seen (and do not recall anyone else reporting) this error
> return.

It was days earlier than this issue and *might* be related to someone
rebooting an NFS server the client is connected to at that time. Hard
to tell for sure without timestamps.

> I'd suggest you first check network connetcivity. Both NFS client and NFS
> server should be able to ping each other.

The network connectivity is OK; network interface error counts are
monitored with munin on all systems, and don't appear to be an issue.

On that specific system's dedicated interface for NFS:

Name    Mtu Network       Address              Ipkts Ierrs Idrop
Opkts Oerrs  Coll
net1   1500 <Link#2>      (redacted) 18754677570     0     0
18598354347     0     0

Also, in both cases (which occurred with different client & server
pairs), there were three different directories from the server mounted
on the client.

One was affected. The other two worked fine. Listing files and
directories. Locking. Calculating hashes of large files.
Creating/writing files. Etc.

E.g. /a /b and /c were mounted from nfs.server and /a and /b were fine
while /c was hung.  (And, as I mentioned before but seems worth
repeating here for completeness, other FreeBSD clients had /c mounted
with no problems while it was hung on this machine.)


> If that is the case, then I'd suggest you capture packets. On the FreeBSD
> end:
> # tcpdump -s 0 -w out.pcap host <nfs-server-name>
> Let this run for a while and then pull out.pcap into wireshark and see what
> traffic is going between the NFS client and server.
> (Unlike tcpdump, wireshark does know how to decode NFS properly.)

If/when the issue happens again, I will attempt to do this and report back.

Thanks!