[Pacemaker] votequorum for 2 node cluster

Kostiantyn Ponomarenko konstantin.ponomarenko at gmail.com
Fri Jun 13 04:51:09 EDT 2014


Thank you for the explanation. I got the point.
But just to be sure, and maybe someone will find this info helpful, wanna
clarify this two options behavior.
>From the http://manpages.ubuntu.com/manpages/saucy/man5/votequorum.5.html
about last_man_standing option:

       NOTES: In order for the cluster to downgrade automatically from 2 nodes
       to a 1 node cluster, the auto_tie_breaker feature must also be enabled.

       If auto_tie_breaker is not enabled, and one more failure


       occurs, the remaining node will not be quorate.


But this is still a roulette - you can lose only the node which
doesn't have the lowest nodeid?

Am I right?



Thank you,
Kostya


On Thu, Jun 12, 2014 at 12:37 PM, Christine Caulfield <ccaulfie at redhat.com>
wrote:

> On 12/06/14 00:51, Andrew Beekhof wrote:
>
>> Chrissy?  Can you shed some light here?
>>
>> On 11 Jun 2014, at 11:26 pm, Kostiantyn Ponomarenko <
>> konstantin.ponomarenko at gmail.com> wrote:
>>
>>  Hi guys,
>>>
>>> I am trying to deal somehow with split brain situation in 2 node cluster
>>> using votequorum.
>>> Here is a quorum section in my corosync.conf:
>>>
>>> provider: corosync_votequorum
>>> expected_votes: 2
>>> wait_for_all: 1
>>> last_man_standing: 1
>>> auto_tie_breaker: 1
>>>
>>> My question is about behavior of the remaining node after I shout down
>>> node with the lowest nodeid.
>>> My expectation is that after a last_man_standing_window this node should
>>> be back working.
>>>
>>> Or in the case of two node cluster it is not a solution?
>>>
>>
>
> If you want symmetric failure handing into a 2 node cluster then the
> two_node option might be more appropriate. auto_tie_breaker and
> last_man_standing are more useful for larger clusters where a network split
> leaves more than one node in a partition.
>
> Chrissie
>
>
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