[Pacemaker] Three questions...

[Dejan Muhamedagic]

Hi,

On Thu, Mar 19, 2009 at 02:09:57PM +0530, Romi Verma wrote:
> actually after going through few previous posts i am kinda  confused.
> 
> In  > 2 nodes cluster , if we configure a ilo stonith (which can control
> only one node at a time) for a particular node then
> 
> 1) running it  on only one node is enough.    ??

Yes, it should be. Even with split brain when the started stonith
resource is on the "wrong" side, it should be started again on
the side which has quorum.

> 2) we should run it as clone on all nodes except for one it has been
> configured??.
> 
> Thanks for your help and Extremely sorry for bothering you  .

Thanks,

Dejan

> 
> 
> On Thu, Mar 19, 2009 at 11:53 AM, Takenaka Kazuhiro <
> takenaka.kazuhiro at oss.ntt.co.jp> wrote:
> 
> > Hello
> >
> >  It is completely dependent on your stonith architecture.
> >> Some devices support a list of hosts which means you only need one
> >> stonith resource.
> >>
> >
> > Even if there is a such device, the Pacemaker stonith mechanism
> > provides insufficient support for it. Suppose: how should its plugin
> > instance do when it loses control to one of its target nodes? If a
> > monitor for the instance returns an error code, Pacemaker loses control
> > via it to all of its target nodes at a time. On the other hand, If a
> > monitor for the instance returns a success code, Pacemaker cannot
> > be aware of the trouble. In the later case, when the node that the
> > instance cannot control must be shooted, Pacemaker will request
> > the useless instance to shoot the node.
> >
> >
> > Andrew Beekhof wrote:
> >
> >> 2009/3/16 Romi Verma <romi3rdfeb at gmail.com>:
> >>
> >>>
> >>>> i guess if DC fails then CRM will elect any other node for DC role and
> >>>> then , this new DC  will try to fence the errant node , if it fails to
> >>>> fence
> >>>> then it will choose other node for this fencing task.
> >>>>
> >>>  Andrew could you please confirm the above .
> >>>
> >>
> >> [insert same rant as Lars - this is getting _really_ annoying]
> >>
> >>  one thing more related to stonith design. suppose we have 4 nodes cluster
> >>> so
> >>> do we need 3 stoniths on each node ( to make a node eligible to kill any
> >>> of
> >>> other 3 nodes ) that will lead to 3x4 stoniths or  do we need only  one
> >>> stonith on  each node that will be total 4 stoniths .
> >>>
> >>
> >> It is completely dependent on your stonith architecture.
> >> Some devices support a list of hosts which means you only need one
> >> stonith resource.
> >>
> >>  i experimented this and found that 3 stoniths on each node is required
> >>> but i
> >>> guess it should not be the c ase as CIB has the stonith info so even if
> >>> stonith is not running on a node it shoul be able to  read the stonith
> >>> related info from CIB.
> >>>
> >>> Thanks,
> >>>
> >>>>
> >>>> Thanks & Regards,
> >>>>
> >>>>
> >>>>> Regards,
> >>>>>
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> >>>>>
> >>>>>
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> >>>>>
> >>>>>
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> >>>>
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> >>>
> >>>
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> >>
> >>
> > --
> > Takenaka Kazuhiro <takenaka.kazuhiro at oss.ntt.co.jp>
> >
> >
> > _______________________________________________
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> > Pacemaker at oss.clusterlabs.org
> > http://oss.clusterlabs.org/mailman/listinfo/pacemaker
> >

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