[Samba] [Patches] AD Database corruption after upgrade from <= 4.6 to 4.7 (bug #13228)

[Ralph Böhme]

On Mon, Jan 22, 2018 at 05:24:44PM +0100, Achim Gottinger via samba wrote:
> Am 22.01.2018 um 10:49 schrieb Stefan Metzmacher via samba:
> > Also DO NOT repair the following errors with samba-tool dbcheck!
> > "Remove duplicate links in attribute"
> > and
> > "ERROR: orphaned backlink"
> > as this removes the ability to repair the database
> > in the next round of patches!
> > 
> I had this error after upgrading from 4.7.3 to 4.7.4 and used samba-tool
> dbcheck --clean to get rid of them.
> Replication is still working. What kind of unrepairable corruption can i
> expect now?

see the bug report for details, this can eg cause loss of group memberships or
generally speaking loss of linked-attributes.

The only remede is comparing all objects for differences in linked-attributes
and restore overwritten forward-links from now dangling backlinks.

We're currently also working on an improvement to dbcheck so it can detect such
corruption and fix it, but this will only work if you did *not* run dbcheck
--fix on the affected database.

-slow

-- 
Ralph Boehme, Samba Team       https://samba.org/
Samba Developer, SerNet GmbH   https://sernet.de/en/samba/