[Pacemaker] Stonith Device APC AP7900

[Dejan Muhamedagic]

Hi,

On Tue, Nov 02, 2010 at 12:10:37PM +0100, Pavlos Parissis wrote:
> On 2 November 2010 11:04, Dejan Muhamedagic <dejanmm at fastmail.fm> wrote:
> 
> > Hi,
> >
> > On Tue, Nov 02, 2010 at 08:08:32AM +0100, Pavlos Parissis wrote:
> > > On 1 November 2010 15:01, Rick Cone <rcone at securepaymentsystems.com>
> > wrote:
> > >
> > > > Dejan,
> > > >
> > > > Below I had:
> > > >
> > > > primitive res_stonith stonith:apcmastersnmp \
> > > >         params ipaddr="192.1.1.109" port="161" community="sps" \
> > > >         op start interval="0" timeout="60s" \
> > > >         op monitor interval="60s" timeout="60s" \
> > > >          op stop interval="0" timeout="60s"
> > > > clone rc_res_stonith res_stonith \
> > > >         meta target-role="Started"
> > > >
> > > > And you commented:
> > > >
> > > > You can also use a single instance setup, i.e. without clones.
> > > >
> > > > What is this "single instance setup", and what would it look like in
> > the
> > > > crm
> > > > configure?
> > >
> > >
> > > You have one already, res_stonith  is your single instance setup.
> >
> > Yes, just don't clone that resource.
> >
> > > What are the pros/cons to this compared to the clone setup I
> > > > have?
> > > >
> > >
> > > The decision of cloned or non-cloned stonith resource is mainly driven
> > about
> > > the ability of the fencing device to accept multiple connections
> > > simultaneously.
> > > If you fencing device doesn't allow that then you can only use a
> > non-cloned
> > > resource.
> >
> > Right.
> >
> >
> Do you know under which conditions pacemaker initiates multiple connections
> to a fencing device?

There are no specific conditions. It can happen by chance because
individual clone instances run independently.

> > The cloned resource will fence a node a bit faster in a case stonith
> > > resource is running on the node to be fenced, there is no need to move
> > the
> > > resource to another node and then fence the node.
> >
> > Did you measure the time it takes to start the stonith resource?
> >
> 
> The last time I tested it was with rackpdu and it took 5 secs for pacemaker
> to move the resource and trigger the reboot event.

So, the time difference is 5 seconds in your case, right?

Cheers,

Dejan

> > > But, cloned resource is has a bit more complex configuration. cloning
> > looks
> > > easy but I bet there is some complexity behind it.
> >
> > There is, but in this simple case where clones are not in any
> > relation to other resources, that shouldn't pose a problem.
> >
> > > I have experiment with both versions on AP9606 using the rackpdu agent
> > and
> > > in both cases worked as expected. Now I am expecting a Aviosys 9258ST and
> > I
> > > will use the non-cloned version.
> >
> > Thanks,
> >
> > Dejan
> >
> >

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