[Linux-cluster] Fwd: CLVM exclusive mode

Xinwei Hu hxinwei at gmail.com
Mon Aug 17 11:17:13 UTC 2009


Hi,

  Attached a very naive try to solve the issue you have.

  Would you give it a test ?

  Thanks.

2009/8/16 brem belguebli <brem.belguebli at gmail.com>:
> Hi,
>
> I don't think adding more security can be considered as pointless,
> especially when this has no impact on performance or behaviour.
> The question is, what's the point in  allowing the clustered active
> exclusive lock to be bypassed ?
>
> In comparison to other volume management solutions (on various unices) where
> these barriers are already implemented, the lack of them on Linux can  be
> seen as a weakness.
> Regards
>
>
> 2009/8/6, Christine Caulfield <ccaulfie at redhat.com>:
>>
>> On 06/08/09 02:52, Jia Ju Zhang wrote:
>>>
>>> Just RFC:
>>> I noticed that 'vgchange -ay' can convert the lock which locked by
>>> 'vgchange -aey'
>>> from EX to CR. Is that acceptable to change the logic into always
>>> allocating a new lock
>>> rather than converting an existing lock?
>>> In that case, 'vgchange -ay' won't change the result of 'vgchange -aey'.
>>> But if we really
>>> want to convert the lock, we can firstly invoke 'vgchange -aen' to
>>> release the EX lock,
>>> then invoke the 'vgchange -ay'.
>>>
>>> Does this make sense? Or what side effect it may introduce?
>>
>>
>> I think it makes no sense at all, and have already said so on this list.
>> As far as I know there is no bugzilla for this problem and therefore it
>> isn't being worked on.
>>
>> So ... if you care about this ... you know what to do ;-)
>>
>> Chrissie
>>
>>>>>> On 8/6/2009 at  9:39 AM, in message<4A7A346B.A94 : 39 : 18251>, Jia Ju
>>>>>> Zhang
>>>
>>> wrote:
>>>>
>>>> On Fri, 2009-07-31 at 21:29 +0200, brem belguebli wrote:
>>>>>
>>>>> Hi,
>>>>>
>>>>> Same behaviour as the one from Rafael.
>>>>>
>>>>> Everything is coherent as long as you use the exclusive flag from the
>>>>> rogue node, the locking does the job. Deactivating an already opened
>>>>> VG (mounted lvol) is not possible either. How could this behave in
>>>>> case one used raw devices instead of FS ?
>>>>>
>>>>> But when you come to ignore the exclusive flag on the rogue node
>>>>> (vgchange -a y vgXX) the locking is completely bypassed. It's
>>>>> definitely here that the watchdog has to be (within the tools
>>>>> lvchange, vgchange, or at dlm level).
>>>>
>>>> Is there an open bugzilla # for this? Would like to follow this issue.
>>>>
>>>
>>>
>>>
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>>
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>
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