Brian, 
first of all thanks for your answer

Il giorno lun, 18/05/2009 alle 09.29 -0500, Brian Kroth ha scritto:
> I remember looking at this a while ago as well and being fairly
> confused.  I'm fairly certain that lvm2 with the use flags you mention
> is the way to go, so you might have to unmask them in your
> /etc/portage/profile/use.mask (add -clvm, -cman).
> 
> OCFS2 generally uses it's own different cluster stack than CMAN (which
> uses openais).  Since I believe 2.6.26 you can use the other one, but I
> haven't found it to be as stable.

I didn't understand here what you mean. Which one is "the other one"?
(maybe it's just my english :P )

>   It also requires quite a bit of extra
> configuration for proper fencing, whereas that's built into the OCFS2
> stack.  Since you're doing this with DRBD it sounds like you're trying
> to do it on the cheap so proper fencing probably isn't available
> anyways.

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.

> If you aren't doing anything with LVM that needs to be cluster aware
> (eg: just a concatenation of multiple PVs, no striping) then it should
> be just fine without CLVM.  The key is that you /must/ take all but one
> node offline (umount; vgchange -an) before you do any LVM operations
> such as adding more extents, else they'll have an inconsistent view of
> the VGs/LVs.  This also isn't technically supported but I've run it
> without problems for a year or so now.

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.

I'll try to unmask those flags and re-emerge lvm2.

Thanks,
	Giacomo