RAFT and CTDB

[Richard Sharpe]

On Mon, Nov 24, 2014 at 7:43 AM, Rowland Penny <repenny241155 at gmail.com> wrote:
> On 24/11/14 15:38, Volker Lendecke wrote:
>>
>> On Mon, Nov 24, 2014 at 03:35:06PM +0000, Rowland Penny wrote:
>>>
>>> On 24/11/14 15:24, Richard Sharpe wrote:
>>>>
>>>> On Sun, Nov 23, 2014 at 9:31 PM, Min Wai Chan <dcmwai at gmail.com> wrote:
>>>>>
>>>>> Dear Steve,
>>>>>
>>>>> Ok ok, Will send it over then there are on one login to the server
>>>>> maybe
>>>>> during mid night.
>>>>>
>>>>> I saw something about the ping_ping -RW test
>>>>> something like below?
>>>>>
>>>>> ping_pong -rw test.dat N
>>>>>
>>>>> Do you need this test result as well?
>>>>>
>>>>> I just wonder if we mount the ocfs2 wrong?
>>>>> If there is a way to mount ocfs2 via user space?
>>>>
>>>> It is not an issue of mounting ocfs2 incorrectly, I believe.
>>>>
>>>> Rather, you have to have their user-space posix locking daemon running.
>>>>
>>> I think I see a possible answer, does this mean that you would get
>>> two locking daemons, the CTDB one AND the OCFS2 one ??
>>
>> Assuming ocfs2 really requires a daemon to do fcntl locking,
>> then yes, there will be two daemons. ctdb will rely on
>> ocfs2's daemon for the reclockfile. Both serve different
>> purposes.
>>
>> Volker
>>
> OK, but would/could they work together, or could they interfere with each
> other and cause problems with the smbd daemon i.e stop it starting.

Firstly, Ralph is correct. ctdb does not use a locking daemon.

What happens is that the ctdb recovery daemon tries to take out an
fcntl lock on an ocfs2 file in the cluster. This is sent to their
user-space lock daemon that uses Corosync Closed Process Groups to
implement their distributed lock manager. If their DLM is not running
or not properly configured you will have problems and ctdb will be
unable to come up correctly.

They are two separate daemons performing separate functions.

I do not have an OCFS2 setup but it would be good to get to the bottom of this.

-- 
Regards,
Richard Sharpe
(何以解憂？唯有杜康。--曹操)