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Subject: Re: safe versions of NFS
From:   hedrick@rutgers.edu
In-Reply-To: <e6501675-7cb4-6f5b-78f7-abb1be332a34@math.utexas.edu>
Date:   Tue, 13 Apr 2021 11:17:18 -0400
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 <e6501675-7cb4-6f5b-78f7-abb1be332a34@math.utexas.edu>
To:     Patrick Goetz <pgoetz@math.utexas.edu>
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many, though not all, of the problems are =E2=80=9Clock reclaim failed=E2=
=80=9D.

> On Apr 13, 2021, at 10:52 AM, Patrick Goetz <pgoetz@math.utexas.edu> wrot=
e:
>=20
> I use NFS 4.2 with Ubuntu 18/20 workstations and Ubuntu 18/20 servers and=
 haven't had any problems.
>=20
> Check your configuration files; the last time I experienced something lik=
e this it's because I inadvertently used the same fsid on two different exp=
orts. Also recommend exporting top level directories only.  Bind mount ever=
ything you want to export into /srv/nfs and only export those directories. =
According to Bruce F. this doesn't buy you any security (I still don't unde=
rstand why), but it makes for a cleaner system configuration.
>=20
> On 4/13/21 9:33 AM, hedrick@rutgers.edu wrote:
>> I am in charge of a large computer science dept computing infrastructure=
. We have a variety of student and develo9pment users. If there are problem=
s we=E2=80=99ll see them.
>> We use an Ubuntu 20 server, with NVMe storage.
>> I=E2=80=99ve just had to move Centos 7 and Ubuntu 18 to use NFS 4.0. We =
had hangs with NFS 4.1 and 4.2. Files would appear to be locked, although e=
ventually the lock would time out. It=E2=80=99s too soon to be sure that mo=
ving back to NFS 4.0 will fix it. Next is either NFS 3 or disabling delegat=
ions on the server.
>> Are there known versions of NFS that are safe to use in production for v=
arious kernel versions? The one we=E2=80=99re most interested in is Ubuntu =
20, which can be anything from 5.4 to 5.8.