samba - Nov 2011 - One single SAN, one LUN, two servers : CTDB ? GFS2 ?

Hi,

My Samba setup is getting nicer : Likewise-open is working fine, winbind 
is stopped, ACLs are OK, file serving is going smoothly...

Now I have to store all these data on a SAN, and serve it through two 
servers.
I read a lot of docs about this, and CTDB seems mandatory to prevent 
locking, lack of consistency of my files and seems the way to go.
CTDB relies on a clustered filesystem and amongst the candidates, it 
seems GFS2 is the one we'll choose.

Questions :
1 - Did I understand well the situation and the components involved?
2 - Is it possible to setup GFS2 with 2 servers using the same LUN?

-- 
Nicolas Ecarnot