[Gluster-users] split-brain recovery automation, any plans?

[Pranith Kumar Karampuri]

On Tue, Jul 12, 2016 at 9:27 PM, Dmitry Melekhov <dm at belkam.com> wrote:

>
>
> 12.07.2016 17:38, Pranith Kumar Karampuri пишет:
>
> Did you wait for heals to complete  before upgrading second node?
>
>
> no...
>

So basically if you have operations in progress on the mount, you should
wait for heals to complete before you upgrade second node. If you have all
the operations on all the mounts stopped or you unmounted all the mounts
for the volume, then you can upgrade all the servers one by one then
clients. Otherwise it will lead to problems. That said in 3 way replica it
shouldn't cause split-brains. So I would like to know exact steps that lead
to this problem. We know of one issue which leads to split-brains in case
of VM workloads where we take down bricks in cyclic manner without waiting
for heals to complete. I wonder if the steps that lead to split-brain on
your setup are similar. We are targetting this for future releases...


>
>
>
> On Tue, Jul 12, 2016 at 3:08 PM, Dmitry Melekhov <dm at belkam.com> wrote:
>
>> 12.07.2016 13:31, Pranith Kumar Karampuri пишет:
>>
>>
>>
>> On Mon, Jul 11, 2016 at 2:26 PM, Dmitry Melekhov < <dm at belkam.com>
>> dm at belkam.com> wrote:
>>
>>> 11.07.2016 12:47, Gandalf Corvotempesta пишет:
>>>
>>>> 2016-07-11 9:54 GMT+02:00 Dmitry Melekhov < <dm at belkam.com>
>>>> dm at belkam.com>:
>>>>
>>>>> We just got split-brain during update to 3.7.13 ;-)
>>>>>
>>>> This is an interesting point.
>>>> Could you please tell me which replica count did you set ?
>>>>
>>>
>>> 3
>>>
>>>>
>>>> With replica "3" split brain should not occurs, right ?
>>>>
>>>
>>> I guess we did something wrong :-)
>>
>>
>> Or there is a bug we never found? Could you please share details about
>> what you did?
>>
>>
>> upgraded to 3.7.13 from 3.7.11 using yum, while at least one VM is
>> running :-)
>> on all 3 servers, one by one:
>>
>> yum upgrade
>> systemctl stop glusterd
>> than killed glusterfsd processes using kill
>> and systemctl start glusterd
>>
>> then next server....
>>
>> after this we tried to restart VM, but it failed, because we forget to
>> restart libvirtd, and it used old libraries,
>> I guess this is point where we got this problem.
>>
>>
>>
>>>
>>> I'm planning a new cluster and I would like to be protected against
>>>> split brains.
>>>>
>>>
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>>>
>>
>>
>>
>> --
>> Pranith
>>
>>
>>
>
>
> --
> Pranith
>
>
>


-- 
Pranith
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