I have been trying to setup PDC/BDC samba servers without much luck so far.
I followed various HOWTOs , and as far as PAM autentication - everything worked like a charm - but windows machines never joined the domain. All setups I tried involved group mapping and winbind.
In my requirements users are all local administrators and are mapped to their Unix uids by their username. The file security is provided by UNIX groups and everything is working fine. At the moment Samba is using a passwd file backend.

The need for LDAP arose from desire to have a BDC and failover.
Is it possible to replace PAM autentication with ldap on both servers (it is! Easy!) and Use Ldap backends for both Samba servers?
I do not think that even samba.schema will be necessary in my case. Am I right?

But I cannot get it to work It should work!!! Don't understand.

PS and another question: There is no /etc/samba/smbpasswd file with LDAP setup. Do we still need to "smbpasswd -a" users? Nothing seems to happen when you do.