Hi,

On Fri, Aug 19, 2011 at 11:45:24AM +0200, Maloja01 wrote:
> On 08/18/2011 12:19 PM, Ulrich Windl wrote:
> > Hi!
> > 
> > Reading the docs, I learned that pacemaker understands more complex 
> > dependencies than "group" where resources are strictly sequential. For 
> > example one could start a set of resources in parallel, then wait until all 
> > are done, then start another set of resources, etc.
> > 
> > Now I wonder:
> > 1) Can such a thing (i.e. parallelism) be configured with crm shell? If so, 
> > what is the syntax like?
> 
> If you have two resources like primitives and they do not have any order
> constraints (neither explizit by a order constraint nor implizit by
> membership in group) such resources are assumed be
> "startable"/"stopable" in parallel and the cluster will do not have any
> peferences about the order.

I guess that he meant resource sets. There's a slight confusion
regarding those and they were to be reimplemented/redefined in
CRM. Don't know what's the current status.

> > 2) In some resource groups, not all resources are really required. For 
> > example in a RAID1, only one of both legs is really required to start up 
> > the RAID (assuming I need to activate some extra resource for each leg of 
> > the RAID). Can such a dependency be expressed in CRM? If so, how do you do 
> > it?
> 
> Beside the fact that I do not see the both legs/ 2 x single leg
> ressources for RAID1 I would say yes that possible but will increase
> the complexity of the cluster and the most important idea behind
> clustering is: "keep it simple". In your case the critical point could
> be the "OR" in the oredring of costraints.
> 
> All resouces after your 2 legs solution could be started, if Leg1 OR
> Leg2 is up. Maybe that has to be described via ordering constraints.

That cannot be described currently, i.e. start B if at least one
of A1 and A2 are running.

Thanks,

Dejan


> > I'd wish (I know what you will reply ;-)) that could be expressed with the 
> > crm shell.
> really? - why I wrote my answer, if you already knew it ;-)
> 
> > 
> > Regards,
> > Ulrich
> > 
> > 
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