[pgpool-hackers: 3982] Re: [pgpool-general: 7543] VIP with one node

[Tatsuo Ishii]

> Hi Ishii_San
> 
> Your understanding is correct for the proposal. Basically IMHO whatever we
> do for trying to remedy that original issue there will always be a chance
> of split-brain.

Right.

> The reason I am proposing this solution is that with this proposed design
> the behaviour
> would be configurable. For example if user set wd_lost_node_to_remove_timeout
> = 0
> then this will disable the lost node removal function and eventually the
> watchdog would
> behave as it does currently.
> And normally I expect this wd_lost_node_to_remove_timeout value to be set
> in the
> range of 5 to 10 mins. Because blackout for more than 5 to 10 mins would
> mean
> there is some serious problem in the network that a node is unable to
> community for
> such a long period of time and we need resume the service even if it comes
> with
> the risk of a split-brain.

Ok.

> The second part of proposal talks about the nodes that are properly shut
> down. In that
> case, the proposal is to stop counting those nodes towards the quorum
> calculation since
> we already know that these nodes are not alive anymore.

Is it possible to configure watchdog to enable the lost node removal
function only when a node is properly shutdown?

> But again it also
> have associated
> risks in case the previously shutdown node got started again but unable to
> communicate
> with existing cluster.

Fair point.

Best regards,
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese:http://www.sraoss.co.jp