On Mon, 2009-05-18 at 14:39 -0500, Brian Kroth wrote:

> Since 2.6.26, OCFS2 has two cluster stacks available to it:
> - ocfs2_stack_o2cb:  which is the original stack
> - ocfs2_stack_user:  which is the one that requires cman and openais

oh, I missed it completely.
I'm using the first one :)

> > Yes, you're right. The only way I have to get a sort of STONITH (if it
> > can be used, I've still to check this) is IPMI which is working well so
> > far.
> 
> I believe that will work just fine.

hoping so, after a quick search I've seen IPMI agents for heartbeat and
for fenced.
 
> > The problem is that a node will use (mount) some LVs and the other one
> > some others. So I can't do the fast way as you suggest, as I need to
> > stop all services that use data on LVs before unmounting.
> 
> But, with OCFS2 you can (even temporarily) have a single node mount all
> the LVs, move your service IPs over, and _then_ umount and stop them on
> the other one while you do your changes and then remount them all.
> That's the great things amount a clustered fs - more than one node can
> play in the sandbox without problems.

Uh, that can be an option. It seems even a scriptable work, with a bit
of effort and error-checking, but it seems doable in the end. Will check
that, thanks.

> Also, I'm gonna put a plug in for Heartbeat [1] for service management.
> It's much more powerful than rgmanager in my opinion.  If you're dead
> set on using the openais cluster stack you can also use pacemaker [2].
>The model I typically use for Heartbeat, is to have it run a couple of
> dummy monitoring scripts as resource agents clones that each set an
> attribute as to the service's health on a machine.  Then using the value
> of that attribute I setup rules to move service IPs to the "healthiest"
> node, where your definition of "healthiest" is completely dependent upon
> your monitoring scripts.
> 
Again, thanks for the pointers. Expecially pacemaker of which I did not
know the existence.

	Giacomo