Re: FreeBSD 13.2 NFS client mount hangs

On Mon, Oct 9, 2023 at 2:37 AM J David <j.david.lists@gmail.com> wrote:
>
> On Mon, Oct 9, 2023 at 1:34 AM Rick Macklem <rick.macklem@gmail.com> wrote:
> > LocalOwn and LocalOpens indicate that the server did start issuing
> > delegations.
>
> Yes, with that enabled, the Delegs value from "nfsstat -Ec" climbs
> into the low thousands. Performance does seem (gut feeling, not
> tested) to be improved until the LocalOwns/LocalOpens pile up.
>
> > All I can think of is that you have an environment where the
> > same file(s) get open'd by multiple processes.
>
> Yes.
>
> > The "oneopenown" option at least ensures that there is a single
> > open owner (without it, each process is a separate open owner).
>
> I don't know what issue the "It may not work correctly when
> Delegations are being issued by a server" warning about oneopenown
> refers to.
>
> Would that potential problem still be a concern if the only filesystem
> mounted with oneopenown were also mounted readonly and with nolockd?
> (Specifically: ro,nfsv4,minorversion=2,tcp,nosuid,noatime,nolockd,oneopenown)
Yes. With "oneopenown" all NFSv4 Opens (not the same as a POSIX open, they
are a Windows like open lock) are tied to the same open_owner string. However,
local opens are tied to open_owner strings that are created from the process.
--> As such, delegations and "oneopenown" do not mix well.

rick

>
> Thanks!