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Subject: Re: NFS Mount Hangs
From:   Jason Breitman <jbreitman@tildenparkcapital.com>
In-Reply-To: <94F7249D-20B1-437F-B383-D142B638DFAE@tildenparkcapital.com>
Date:   Wed, 10 Mar 2021 10:50:54 -0500
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To:     Trond Myklebust <trondmy@hammerspace.com>
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Do you know of a FreeBSD 12.X kernel that has the fix you suggested or is there a kernel setting that I can apply to eliminate the issue?

Jason Breitman


On Mar 8, 2021, at 10:32 PM, Jason Breitman <jbreitman@tildenparkcapital.com> wrote:

The server is running FreeBSD 12.1-RELEASE-p5.

Jason Breitman

On Mar 8, 2021, at 8:52 PM, Trond Myklebust <trondmy@hammerspace.com> wrote:

On Mon, 2021-03-08 at 17:22 -0500, Jason Breitman wrote:
> Thank you.
> Do you know which kernel version is fixed?
> If not, is there something I can look for in the source code that
> will indicate that the kernel is fixed.
> 

As I said, the problem here is that the server doesn't seem to be
closing the socket when the client does. You didn't actually tell us
which server you are using, so I don't know how to answer that
question.


> Jason Breitman
> 
> 
> On Mar 8, 2021, at 5:15 PM, Trond Myklebust <trondmy@hammerspace.com>
> wrote:
> 
> On Mon, 2021-03-08 at 13:16 -0500, Jason Breitman wrote:
>> Issue
>> NFSv4 mounts periodically hang on the NFS Client.
>> 
>> During this time, it is possible to manually mount from another NFS
>> Server on the NFS Client having issues.
>> Also, other NFS Clients are successfully mounting from the NFS
>> Server
>> in question.
>> Rebooting the NFS Client appears to be the only solution.
>> 
>> I believe this issue has been discussed in the past so I included
>> an
>> article that matched my symptoms.
>> I do not see a case statement for FIN_WAIT2 at
>> https://elixir.bootlin.com/linux/v4.19.171/source/net/sunrpc/xprtsock.c
>> .
>> 
>> NFS Client
>> OS:             Debian Buster 10.8
>> Kernel: 4.19.171-2
>> Protocol:       NFSv4 with Kerberos Security
>> Mount Options:  nfs-
>> server.domain.com:/data     /mnt/data       nfs4   
>> lookupcache=pos,n
>> oresvport,sec=krb5,hard,rsize=1048576,wsize=1048576    00
>> 
>> Output from the NFS Client when the issue occurs
>> # netstat -an | grep NFS.Server.IP.X
>> tcp        0      0 NFS.Client.IP.X:46896     
>> NFS.Server.IP.X:2049       FIN_WAIT2
>> 
> 
> Your client has closed the connection, and is waiting for the server
> to
> close the connection on its side.
> 
> I'd suggest using a newer kernel, or else getting someone in the
> Debian
> project to fix theirs.
> 

-- 
Trond Myklebust
CTO, Hammerspace Inc
4984 El Camino Real, Suite 208
Los Altos, CA 94022
​
www.hammer.space