[Linux-cluster] Protocol compatibility of DLM/Corosync across versions

[David Teigland]

On Sun, Dec 18, 2016 at 08:46:25PM +0100, Jean-Marc Saffroy wrote:
> Hi (again),
> 
> Another question I have regarding DLM and Corosync (because Corosync is 
> required to use DLM): should I expect compatibility across versions?
> 
> I did a quick test between distributions running different kernels (CentOS 
> 6, Centos7 and Ubuntu 14) but rather close versions of Corosync, and that 
> test worked, but I am not sure if that was just luck. ;)

I can only speak for the dlm part of that.  Between different
distributions, I'd call it luck :)  Within the context of one distribution
things shouldn't break if the distribution is doing it's job.  Upstream,
with no distribution context, I'm certainly aware of when compatibility
breaks between dlm_controld and corosync and between different
dlm_controld versions on nodes.  I try to avoid it, but there are
unpredictable reasons that it can break.

Dave