Hi,

On Sat, Feb 28, 2009 at 09:53:24AM +0100, Andrew Beekhof wrote:
> On Fri, Feb 27, 2009 at 22:32, Andreas Mock <[email protected]> wrote:
> >> -----Urspr?ngliche Nachricht-----
> >> Von: "Andrew Beekhof" <[email protected]>
> >> Gesendet: 16.02.09 11:23:53
> >> An: ?General Linux-HA mailing list <[email protected]>
> >> Betreff: Re: [Linux-HA] Generell STONITH resource configuration question
> >
> > Hi all,
> >
> >> >
> >> > Just to get it right, I'm using IPMI as STONITH device. I have to set up
> >> > two resources in a 2-Node cluster and add constraints in order to force
> >> > each resource to run on a separate nodes.
> >> >
> >> > Is this approach correct? Anything else I need to worry about when
> >> > creating the constraints / resources?
> >>
> >> You might be able to run it as a clone which would eliminate the need
> >> for any constraints.
> >
> > I want to emphasis one issue. Some of the stonith devices (not stonith 
> > plugins)
> > are not "cloneable". I don't know if it's true for IPMI but there are 
> > stonith devices
> > which do allow only ONE connection at a time. With a "cloned" config you 
> > can NOT
> > define that the status call to the stonith plugins shall be done in a 
> > controlled
> > sequence. That means, IMHO, if you use a "cloned" config it can happen that
> > both (2-node cluster) sides try to do the status operation at the same time.
> > One of them can be rejected (=> bad status).
> 
> Another option for such devices might be to use a Master/Slave and
> only have the master do monitoring.
> I wonder if the lrm hooks for stonith can handle this.

Don't see any reason why they shouldn't.

> > We discussed this once and came to the conclusion that a stonith plugin
> > developer should document if this plugin is "cloneable" reliably.
> >
> > Correct me if something changed the last months in the stonith subsystem
> > which does falsify my "theory".

Your theory is without fault.

Thanks,

Dejan

> > Best regards
> > Andreas Mock
> >
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> >
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