Re: [Qemu-devel] [PATCH v2 0/3] colo: Add support for continious replication

[Lukas Straub <lukasstraub2@web.de>]

On Thu, 15 Aug 2019 19:57:37 +0100
"Dr. David Alan Gilbert" <dgilbert@redhat.com> wrote:

> * Lukas Straub (lukasstraub2@web.de) wrote:
> > Hello Everyone,
> > These Patches add support for continious replication to colo.
> > Please review.
>
>
> OK, for those who haven't followed COLO for so long; 'continuous
> replication' is when after the first primary fails, you can promote the
> original secondary to a new primary and start replicating again;
>
> i.e. current COLO gives you
>
> p<->s
>     <primary fails>
>     s
>
> with your patches you can do
>
>     s becomes p2
>     p2<->s2
>
> and you're back to being resilient again.
>
> Which is great; because that was always an important missing piece.
>
> Do you have some test scripts/setup for this - it would be great
> to automate some testing.

My Plan is to write a Pacemaker Resource Agent[1] for qemu-colo and
then do some long-term testing in my small cluster here. Writing
standalone tests using that Resource Agent should be easy, it just needs
to be provided with the right arguments and environment Variables.

Regards,
Lukas Straub

[1] https://github.com/ClusterLabs/resource-agents/blob/master/doc/dev-guides/ra-dev-guide.asc#what-is-a-resource-agent