[rabbitmq-discuss] rabbitmq-discuss Digest, Vol 52, Issue 7

[Elias Levy]

On Wed, Sep 7, 2011 at 4:00 AM,
<rabbitmq-discuss-request at lists.rabbitmq.com> wrote:
>
> Date: Tue, 6 Sep 2011 18:07:32 +0100
> From: Matthew Sackman <matthew at rabbitmq.com>
>
> Sorry about that - it managed to slip down a crack...

No problem.  Thank you for the reply.

>
> > What happens to persisted messages in mirrored queue slaves if they are
> > restarted and they don't find a queue master?
>
> In the event that the entire cluster is stopped, due to mnesia, it's
> normally required that the last node down comes up first - indeed the
> other nodes in the cluster may very well refuse to start up (they'll
> just block in the "starting database" step) until the nodes that were
> alive when it died reappear.

Is there some timeout on this?  What if the old master is fully fried
and won't be joining the cluster again?  Is there some sort of
election within the remaining nodes to select a new master?  If so,
how is the election resolved?  Slaves most closely synchronized to the
old master wins?

>
> However, in catastrophic cases, such as instantaneous powerloss to the
> whole cluster subsequent startup may well not be as orderly. In this
> case, it's possible that the first node to recover that contained a
> mirror of the queue, regardless of whether it was a master or slave,
> takes the role of master. All other mirrors will then become slaves.

Presumably it ways for a while and then timeouts and becomes master, yes?

Elias Levy