How to backup/restore in multipe DCs domain?

[hyoscar wu]

Hi list,

  I refer https://wiki.samba.org/index.php/Backup_and_Recovery to do
backup/restore and my samba4 ADDC machine works well in single-DC doamin.

  My multiple DCs domain test is as below:

    machineA : samba-4.0.5 , create domain "abc.test"
    machineB : samba-4.0.5 , join "abc.test" as additional DC.

    My scenario is machineA failed , I need to restore it.

    1. After machineB joining, do backup in machineA.
    2. create some user accounts on machineA and machineB.
    3. A few minutes later, check database synchronized, both machine
      has same user accounts.
    4. restore machineA.
    5. A few minutes later, check database synchronized, both machine
      has same user accounts.

  After these 5 steps, machineA gets user accounts from machineB but
machineA can not work well in many situation. For example, machineA can not
create user.

    # /usr/local/samba/bin/samba-tool user add aaaq pass123 at aaaq

ERROR(ldb): Failed to add user 'aaaq':  -
../lib/ldb/ldb_tdb/ldb_index.c:1199: Failed to re-index objectSid in
CN=aaaq,CN=Users,DC=ggg,DC=org - ../lib/ldb/ldb_tdb/ldb_index.c:1131:
unique index violation on objectSid in CN=aaaq,CN=Users,DC=ggg,DC=org

   I know that I can do seize role in machineB then machineA rejoin to
domain. I have some questions about samba4 backup/restore.

    1. If samba4 backup/restore just for single DC domain?
    2. If not , how should I do in multiple DCs domain?
    3. If machineA failed, what is the best way to recover machineA? rejoin
domain , restore or any other way?


Hyoscar