samba4 high availability

[Matthieu PATOU]

Dear all,

I was wondering if it was a correct solution to achieve domain controller high availability by duplicating in real-time 
the samba directory   (and maybe bind zones also) via DRDB and heartbeat/carp.

Heartbeat will be responsible of transferring IP address and starting a samba controller on the heartbeat slave in case 
of failure of the master.

I know that it is also possible to achieve HA mostly out of the box by using open ldap as ldap backend, but is it 
possible to upgrade from samba built-in ldap backend to another one without provisioning  ? and what about sysvol and 
netlogon share in this case ?

Matthieu