[Linux-cluster] quorum

[Prathyush]

I have the below scenario,
I have made the first node down the service failover to second node,then I
switched off second node ,service again swiched to third node,the quorum
was not lost,it adjusted automatically
On Mar 22, 2013 9:11 PM, "Digimer" <lists at alteeve.ca> wrote:

> This is correct.
>
> Quorum needs "50% + 1" of the votes. So in Prathyush's cluster of 3
> nodes/3 votes;
>
> 3 / 2 == 1.5 rounded up is 2.
>
> So once the second node shut down, quorum was lost. With quorum lost, the
> remaining node will stop all of it's clustered services because it can no
> longer be sure what the other nodes are doing. For example, the other two
> nodes might turn back on, fail to connect to the one remaining node, decide
> they have quorum and start clustered services. This would lead to a split
> brain.
>
> If you want a 3-node cluster to work with just one node, consider adding a
> quorum disk, assuming you have a SAN. This would add 2 votes to the
> cluster. So the new math would be;
>
> 5/2 == 2.5 rounded up to 3.
>
> The quorum disk would give it's two votes to the remaining single node for
> a total of 3 votes, thus giving it quorum and allowing it to operate on
> it's own.
>
> digimer
>
> On 03/22/2013 03:16 AM, emmanuel segura wrote:
>
>> Hello
>>
>> If i understand well, you 3 node(3 total votes) and you poweroff 2, 3 -
>> 2 = 1(quorum loss) remain less 50% of votes
>>
>> can you show your config and your log, without it's so hard help you
>>
>> Thanks
>>
>> 2013/3/22 Prathyush <prathyush.r at gmail.com <mailto:prathyush.r at gmail.com>
>> **>
>>
>>     HI,
>>
>>
>>     I have 3 node  cluster with 1 vote each ,and  decided to shut down
>>     the 2 nodes for  maintenance .
>>     When a proper power off /init 0 given to two of the nodes ,i never
>>     loses the quorum
>>     When i am making  force power off (switching off the power/pulling
>>     the power cable) quorum  was lost and services failed in the third
>> node.
>>     why this is happening... any idea
>>     --
>>     /*Regards,
>>     Prathyush*/
>>
>
>
> --
> Digimer
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