[Linux-cluster] relationship corosync + dlm + cman in cluster 3.1.3

[Andrew Beekhof]

On Wed, Jun 22, 2011 at 5:55 PM, Jeroen Koekkoek <j.koekkoek at perrit.nl> wrote:
> Hi,
>
> I have a question regarding the relationship between Corosync, DLM, and CMAN. Is the following statement correct?
>
> The DLM is a kernel module, dlm_controld is the control daemon.
> CMAN is the old messaging layer, and is now stacked on OpenAIS, which in turn is stacked on Corosync.
>
> The DLM does not use CMAN (or Corosync for that matter) to communicate, but does fetch node information from CMAN.
>
> The filesystem (GFS or OCFS2) speaks to the DLM locally (in kernel?) and the DLM takes care of the communication.
>
>
> Now for the real question.
>
> In the 3.1.3 release dlm_controld still depends on CMAN, but is it safe to say that I can just use Pacemaker and Heartbeat resource agents and only install CMAN so that dlm_controld can query node information?
>
> Or did I misunderstand the documentation?

You need to make sure everyone is getting the same membership and
quorum information.
So yes, install CMAN for dlm_controld but also tell pacemaker to use
it too (make sure you're on 1.1.5 or higher).

>
> Regards,
> Jeroen
>
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