[DRBD-user] Question about Linux-HA, stonith and data loss

paddy paddy at panici.net
Wed Jan 11 20:53:59 CET 2006

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

On Wed, Jan 11, 2006 at 08:55:06AM -0500, Todd Denniston wrote:
> paddy wrote:
> >Hi,
> >
> >apologies/errata to previous outporing:
> >
> >obviously, when to stonith is an HA issue.
> >
> >interesting that stonith assumes a network on which you can at least
> >send in at least one direction.
> Which of the stonith plugins are you saying that about?
> http://linux-ha.org/ConfiguringStonithPlugins
> Obviously the ssh plugins have that problem, but at least some of the 
> others connect to a device external to the other node and can brutally 
> bring the power of the other node to 0, with out the other node's network 
> working.

Sorry for what is probably me brutally redefining a few words,
but that's probably the least of my sins.

With hindsight, my posts last night weren't exactly of the standard I'd 
like to aspire to.

But what on earth was I talking about?

I didn't mean "the network" in the sense of the ethernet, ip, serial or what 
have you between the two nodes.  I meant "a network" in the sense of could
be a bloke on roller skates whizzing up and down the aisles of racks looking
for a flashing light, as long as it takes information from A to B :)
(although I'd prefer something with wires myself ;)

And I wasn't thinking of a specific implementation of stonith, so much
as the idea of killing another node.  I'm not sure if there is a real
world application for being able to kill another node without knowing !
Shades of Dr. Strangelove ;)

And I went so far as to suppose that someone might want to let two nodes
race to kill each other if that got you running faster, without really 
stopping to think about how and why.

And I'm sure it all _meant_ something ... ;)

As wild speculation and random disconnected communication goes, I thought
this email was an improvement on the previous one, on a less is more basis.
This morning I figured I'd go with the whole on-parade philosophy: if you
notice something is wrong, don't move a muscle and hope noone else notices!
But you have saved me from that ;)

Apologies to all concerned.

Perl 6 will give you the big knob. -- Larry Wall

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