[Samba] second DC behavior when first switched off

[Sam]

Hello all,

I'm always trying to migrate from W2000 server to Samba 4.

For doing this, I tried this :
- install a W2003 server with AD and DNS services, join it to W2000, 
transfer roles and after demote the old W2000 -> done
- install a Sernet Samba4 with Bind9, join W2003, transfer all 7 roles 
-> done ( thanks to Rowland )

the sync process is working well in two way, I can manage DNS and AD 
with rsat tool even directly connected on the Samba4 server

But the samba4 server does not have a good behavior when I switch off 
the W2003 server...

For example in this case ( W2003 switched off ), if I try to use RSAT AD 
user and group connected to Samba and go to the directory "Domain 
Controllers" I see an error message "domain controllers data not 
available..."
and in the samba4 syslog :

May 21 11:09:09 S4 samba[2455]: [2015/05/21 11:09:09.682170,  0] 
../lib/ldb-samba/ldb_wrap.c:71(ldb_wrap_debug)
May 21 11:09:09 S4 samba[2455]:   ldb: acl_read: CN=W2003,OU=Domain 
Controllers,DC=ariane,DC=intra cannot find attr[msDS-isRODC] in of schema
May 21 11:09:09 S4 samba[2455]:

It seems that it missing a Samba4 entry? For asking Samba4 too?

Another question... How to be sure that the sync process between 2 AD is 
fully terminated and that the servers are ready for a demote process?

Thanks a lot!

Sam