[Samba] CTDB and locking issues in 4.4.6 (Classic domain)

Alex Crow acrow at integrafin.co.uk
Wed Nov 2 19:41:05 UTC 2016

On 02/11/16 11:29, Alex Crow via samba wrote:
> On 02/11/16 07:29, Ralph Böhme wrote:
>> On Tue, Nov 01, 2016 at 09:56:06PM +0000, Alex Crow wrote:
>>>> well, yes and no. I did find some time to look into those logs and
>>>> those just tell use, that the second smbd on the second node that
>>>> fetches the lock record from the (clustered) locking db doesn't see
>>>> the record from the first node. ctdb debug logs might be telling, so
>>>> posting a full set of smbd and ctdb logs to the mailing list would be
>>>> the next step.
>>>> Currently I have no idea how this can happen, getting to the bottom of
>>>> this is certainly fun and entertaining, but also very time
>>>> consuming. At the moment I don't have the time to do this in my free
>>>> time, maybe someone else from the mailing list has.
>>>> -slow
>>> Hi Ralph,
>>> Thanks for that. Can I post the above back to the ML with links to
>>> appropriate logs?
>> sure.
>> Btw, I forgot to mention that I did test this on my own devel cluster,
>> both development version from git master as well as production 4.4,
>> and could not reproduce the issue.
>> -slow
> Is anyone able to assist with this issue? I have produced level 10
> logs but not sure how to debug CTDB.
> As a quick reminder the problem is that locks on one server are not
> being honoured when a client connects to another server in the cluster.
> Cheers
> Alex
FYI When I reset my cluster for two nodes and upgraded from 4,4,6 to
4.4.7, restarted all services the locking worked between two clients
accessing different servers.

So my next step was to add back the 3rd server. At this point, clients
would see locking working OK on the 1st and 2nd servers but opening the
same file from the 3rd server from the 2nd client allowed all access.

It's almost as if if you establish a cluster with 2 CTDB servers
everything works OK but it all goes to hell when you add a 3rd member.,
In all cases the file was initially opened R/W from the 1st client to
the 1st server.

To clarify: by "Nth server" I mean the virtual IPs set up by CTDB in
numerical order.

I would hope this helps anyone that's looking at this.

Best regards


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