[ClusterLabs] Antw: Re: 2-Node Cluster Pointless?

[Andrei Borzenkov]

18.04.2017 10:47, Ulrich Windl пишет:
...
>>
>> Now let me come back to quorum vs. stonith;
>>
>> Said simply; Quorum is a tool for when everything is working. Fencing is
>> a tool for when things go wrong.
> 
> I'd say: Quorum is the tool to decide who'll be alive and who's going to die,
> and STONITH is the tool to make nodes die.

If I had PROD, QA and DEV in a cluster and PROD were separated from
QA+DEV I'd be very sad if PROD were shut down.

The notion of simple node majority as kill policy is not appropriate as
well as simple node based delays. I wish pacemaker supported scoring
system for resources so that we could base stonith delays on them (the
most important sub-cluster starts fencing first).


> If everything is working you need
> neither quorum nor STONITH.
>

I wonder how SBD fits into this discussion. It is marketed as stonith
agent, but it is based on committing suicide so relies on well-behaving
nodes. Which we by definition cannot trust to behave well, otherwise
we'd not need stonith in the first place.