Hi Andreas,

On Wednesday 13 August 2008 11:07:18 Andreas Mock wrote:
> Hi Andreas,
>
> > -----Ursprüngliche Nachricht-----
> > Von: "Andreas Kurz" <[EMAIL PROTECTED]>
> > Gesendet: 12.08.08 22:27:30
> > An: "General Linux-HA mailing list" <[email protected]>
> > Betreff: Re: [Linux-HA] STONITH, default fencing time, forced-fencing
> >
> > Of course ... one instance should be enough but isn't it safer to make
> > sure that every node is able to stonith any other node ... no matter in
> > which state the complete cluster is?
>
> I thought this too longtime ago. I ended also configuring stonith as
> separate primitive resource for each node and constraints forcing a sonith
> plugin not to run on its controlled node.
>
> Why this: In my case (and I'm pretty sure that's also valid for other
> scenarios) the stonith device can only serve exactly ONE connection. That
> means only one user/plugin can connect to the stonith device at a time. As
> soon as I used clones I couldn't guarantee that only one clone connects to
> the stonith device at one time. The monitor action is implemented as a
> connection attempt with gathering some more or less meaningful status
> information.
> I got many (wrong) monitoring failures. And therefore using clones was not
> appropriate.
>
> Stonith plugin contributors should test and document if the plugin is
> "clone-aware".

Mhm ... yes, this seems to be a problem for some stonith devices. I also saw 
such a behavior sometimes. Personally I always thought the main idea of 
running a stonith clone makes sense for multi (>2) node cluster ... in 
theory ;-)

>
> Another issue is that on a two node cluster the usage of clones where the
> clone instance  running on the node it can't shoot (suicide forbidden) is
> IMHO more or less the same as using one primitive stonith ressource and
> an appropriate constraint avoiding a wrong node/stonith assignment.

I agree .. for two nodes one primitive stonith ressource per node with a 
location constraint is also my preferred way of configuration.

>
> By  the way: I really never got the feeling to understand the stonith
> subsystem and its behaviour more that 60%. Probably I/we have to take Dejan
> for one or more beer and asking him anything we don't know about this. 
> :-))

Good plan! ... I think rather more than only one beer is needed to understand 
all ;-)

Regards,
Andreas

>
> Best regards
> Andreas Mock
>
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