[Info-vax] Wide area cluster, metro area network, seeking info

[Michael Moroney]

On 6/14/2021 12:44 AM, Phillip Helbig (undress to reply) wrote:
> In article <sa6ge0$sra$1 at dont-email.me>, Mark Berryman
> <mark at theberrymans.com> writes:
> 
>> On 6/12/21 1:01 AM, Phillip Helbig (undress to reply) wrote:
>>> In article <sa11hi$cpc$1 at dont-email.me>, Mark Berryman
>>> <mark at theberrymans.com> writes:
>>>
>>>> First, I recommend you ignore the suggestions to add a 3rd node to your
>>>> cluster.  In your situation, it is not really a viable answer.
>>>
>>> It would solve most of the problems you mention below, and also could
>>> serve as a test node.
>>>
>>>> There are configurations that will allow a member of a 2-node cluster to
>>>> automatically continue in the event that the other node fails.
>>>
>>> How?  If one has more votes, it is essential.  If the votes are the
>>> same, both are essential.  Unless you mean a quorum disk.  But it should
>>> be at a third location.
>>>
>>
>> Situation: two separate nodes with no shared storage
>>
>> Configure each node with one vote.  Configure each node to use a local
>> disk as the quorum disk, also with one vote.
>>
>> As the cluster is formed, the nodes will discover that they do not agree
>> on the quorum disk and will exclude it, resulting in quorum being
>> established with the 2 votes provided by the nodes.
>>
>> One node goes down, the other pauses while it recomputes quorum.  In
>> doing so it discovers there is no longer a conflict regarding the quorum
>> disk so it includes it, resulting in two votes which re-achieves quorum
>> and the node continues.
>>
>> When the failed node comes back up, the quorum disks will be excluded
>> again and the cluster will return to its original state.  The danger of
>> this configuration is that, if the communication channel between the two
>> nodes is lost but the nodes remain up, the cluster will partition.  This
>> is addressed in my original posting.
> 
> Is this scenario supported?
> 
No!