[Linux-cluster] What if the fence device doesn't work?

[Janne Peltonen]

On Tue, Nov 21, 2006 at 09:20:20AM -0500, Eric Kerin wrote:
> Janne Peltonen wrote:
> >I do understand the basics. I wouldn't want the cluster suite to think
> >that a node couldn't access a resource such as an FS when it can. It
> >would just be nice to configure the cluster suite so that if one method
> >of fencing fails, it tries another, <SNIP>
> Actually, that's entirely possible.
> 
> See: http://sources.redhat.com/cluster/faq.html#fence_levels 

Thanks for the pointer. I thought I'd read the faq through, but - well.
:) I also thought I'd tried to do that already, but looking back at my
old config, I realized that my different fencing methods were actually
inside one level...

> And here's an example block from the cluster.conf file first it tries 
> ilo (HP Lights Out), and if that fails, apc (APC Network power 
> controller) (the ILO sections is probably not correct, I just thew it in 
> there as an example of how you'd setup the method tags):
>                        <fence>
>                                <method name="ilo">
>                                        <device name="server1-ilo" 
> option="off"/>
>                                        <device name="server1-ilo" 
> option="on"/>
>                                </method>
>                                <method name="apc">
>                                        <device name="APC01a" port="1" 
> option="off"/>
>                                        <device name="APC01b" port="1" 
> option="off"/>
>                                        <device name="APC01a" port="1" 
> option="on"/>
>                                        <device name="APC01b" port="1" 
> option="on"/>
>                                </method>
> 
>                        </fence>

Ok, I tried a similar config and it works fine. Thanks again. One
obstacle less on our way to a xen-csgfs-clustered imap server :)

One thing, though: if the APC controller in the above config fails, it's
still a SPOF. Or is there still something I'm missing?-)

Thanks again for your answer.


--Janne