Re: double used hostuuids - Re: NFS issue - newnfs_request: Wrong session srvslot=1 slot=0, freeing free slot!!

On 27/08/2022 16:18, Rick Macklem wrote:
> Ronald Klop <ronald-lists@klop.ws> wrote:
>> On 8/27/22 00:17, Rick Macklem wrote:
>>> Ganbold Tsagaankhuu <ganbold@gmail.com> wrote:
>>>>> Rick,
>>>>>
>>>>> On Fri, Aug 26, 2022 at 11:18 AM Rick Macklem > ><rmacklem@uoguelph.ca<mailto:rmacklem@uoguelph.ca>> wrote:
>>> Ganbold Tsagaankhuu <ganbold@gmail.com<mailto:ganbold@gmail.com>> wrote:
>>>>>> Hi,
>>>>>>
>>>>>> We are having trouble with NFS running on STABLE:
>>>>>>
>>>>>> Aug 26 02:21:42 iron2 kernel: newnfs_request: Wrong session srvslot=1 slot=0
>>> [stuff snipped]
>>>>>> Aug 26 02:22:46 iron2 kernel: newnfs_request: Wrong session srvslot=1 slot=0
>>>>>> Aug 26 02:22:46 iron2 kernel: freeing free slot!!
>>>>>>
>>>>>> We are running FreeBSD 13.1-STABLE #3 stable/13-n252198-c1434fd2dea: Fri Aug 26 01:51:53 UTC 2022 and mount options are:
>>>>>>
>>>>>> rw,nfsv4,minorversion=1,bg,soft,timeo=20,retrans=5,retrycnt=5
>>>>>> ro,nfsv4,minorversion=1,bg,soft,timeo=20,retrans=5,retrycnt=5
>>>>>>
>>>>>> Is there any fix for this issue?
>>> Oh, and one more thing. If you have multiple clients mounting the
>>> NFSv4 server, make sure they all have unique hostids.
>>> Check /etc/hostid and "sysctl kern.hostuuid". If two clients have the
>>> same kern.hostuuid, there will be lots of trouble.
>>>
>>> rick
>>
>> Just a thought. Is it possible/easy to warn about double used hostuuids >from different client IP addresses?
>> Although that will not help this person using Netapp as a server.
> I don't think so. Same hostuuid implies same system, so how does a
> server know they are two different systems?
> - A client could have multiple IP host addresses, so different client
>    host IP addresses for a TCP connection does not imply different systems.
>
> I can, however, modify the console message the server generates when
> it sees a session has been replaced to include "check clients have
> unique hostuuids", which might help.
>
> I also plan on adding a sentence to "man mount_nfs" about this,
> since I just had an email discussion with someone else where the
> problem turned out to be "same hostuuids for multiple clients"
> and the loss of sessions on the FreeBSD server was the hint that
> clued me in.
>
> At least I now know this configuration issue exists.
>
> rick
>
> Regards,
> Ronald.
>

It well worth adding this I think. I didnt realise this about NFSv4, and 
I do a lot with cloud machines, where I simply clone the discs, and thus 
ended up with many machines with the same hostid. Took me a while to 
work out why my NFS was havign issues...


-pete.