[Samba] Previously extended schema not working in 4.4.0

Jonathan Hunter jmhunter1 at gmail.com
Thu Apr 14 23:32:41 UTC 2016

Thank you Andrew, really appreciated.

I have now run 'samba-tool dbcheck --cross-ncs --fix' and it has
successfully fixed some errors; there were 110 previously, however there
are still 69 remaining after a second pass of dbcheck --fix.

The remaining errors seem to be mainly of this form:

ERROR: duplicate attributeID values for myattrib in replPropertyMetaData on

Fix replPropertyMetaData on MYOBJ=object1,OU=myou,DC=mydomain,DC=org,DC=uk
by removing the duplicate value 0x00290003 for myattrib (keeping
0xbd27f44d5)? [YES]
ERROR: incorrect attributeID values in replPropertyMetaData on

Fix replPropertyMetaData
on MYOBJ=object1,OU=myou,DC=mydomain,DC=org,DC=uk by replacing incorrect
value 0x00290001 for et (new 0x00290001)? [YES]
No rDN found in replPropertyMetaData
for MYOBJ=object1,OU=myou,DC=mydomain,DC=org,DC=uk!

Failed to fix attribute replPropertyMetaData : (19, 'replmd_update_rpmd: No
rDN found in replPropertyMetaData
for MYOBJ=object1,OU=myou,DC=mydomain,DC=org,DC=uk [YES]

I've had a brief look at one of the objects in question
(myobj=object1,ou=myou) using ldbsearch, and it looks OK to my untrained
eye, there is a dn: of MYOBJ=object1,OU=myou,DC=mydomain,DC=org,DC=uk and
also a distringuishedName: of the same; there is a "myobj: object1"
attribute, and the usual objectClass/GUID/etc..

Do you know precisely what it is looking for in terms of rDN in
replPropertyMetaData? I can have a look there and see if I can find it.

Or - given that I have taken a backup via 'ldbsearch -s sub -b
ou=myou,dc=...' - am I better off removing this entire OU (which is the
only place I have created these objects), and restoring it? Can I play back
an LDIF generated via ldbsearch safely - will I get the same GUIDs,
creation dates, etc.?

That does feel a little like 'giving up'; and I am very happy to
investigate further if it will help find any gaps or corner cases that
could be used to improve the codebase - but equally, if this isn't
particularly interesting and it can be quickly fixed by a delete / restore,
then I'm happy to do that also :)

Many thanks


On 14 April 2016 at 20:20, Andrew Bartlett <abartlet at samba.org> wrote:

> On Thu, 2016-04-14 at 18:07 +0100, Jonathan Hunter wrote:
> > On 14 April 2016 at 13:37, Jonathan Hunter <jmhunter1 at gmail.com>
> > wrote:
> >
> > > # samba-tool dbcheck --cross-ncs
> > > Checking 4079 objects
> > > MYOBJ=value,OU=myou,DC=mydomain,DC=org,DC=uk: 0x00290001
> > > MYOBJ=value,OU=myou,DC=mydomain,DC=org,DC=uk: 0x0029000a
> > > MYOBJ=value,OU=myou,DC=mydomain,DC=org,DC=uk: 0x00290004
> > > MYOBJ=value,OU=myou,DC=mydomain,DC=org,DC=uk: 0x0009030e
> > > MYOBJ=value,OU=myou,DC=mydomain,DC=org,DC=uk: 0x00090001
> > > MYOBJ=value,OU=myou,DC=mydomain,DC=org,DC=uk: 0x00020119
> > > MYOBJ=value,OU=myou,DC=mydomain,DC=org,DC=uk: 0x00020002
> > > MYOBJ=value,OU=myou,DC=mydomain,DC=org,DC=uk: 0x00020001
> > > MYOBJ=value,OU=myou,DC=mydomain,DC=org,DC=uk: 0x00000000
> > >
> > ERROR: incorrect attributeID values in replPropertyMetaData on
> > > MYOBJ=value,OU=myou,DC=mydomain,DC=org,DC=uk
> > >
> > > Not fixing incorrect value 0x00290004 with 0xbd27f4d3 for myAttr in
> > > replPropertyMetaData on
> > > MYOBJ=value,OU=myou,DC=mydomain,DC=org,DC=uk
> > >
> >
> > Going back over the results of 'samba-tool dbcheck', it struck me
> > just now
> > that the errors flagged up only appear on objects previously created
> > using
> > my extended schema - these are exactly the same type of errors I am
> > now
> > getting when trying to create more of these objects.
> >
> > So I think that 'samba-tool dbcheck' is displaying the symptom, and
> > in fact
> > running 'samba-tool dbcheck' probably won't help my situation.
> >
> > What could cause the errors shown via 'samba-tool dbcheck'?
> Our DRS replication code with extended schema has been pretty badly
> broken in a number of releases, and so we fixed the bugs and added
> dbcheck rules to fix the damage.  We also added code in Samba to refuse
> to operate when we detect damage at runtime.
> Once you run with --fix it should all get back to normal - thankfully
> we have enough information, just a little scrambled, to fix this up.
> (Those rules are actually some of the best-tested in dbcheck).
> We continue to improve our extended schema code.  Hopefully we will
> have it all solid for 4.5, but it is much, much better in 4.4 than 4.2
> was.
> Andrew Bartlett
> --
> Andrew Bartlett                       http://samba.org/~abartlet/
> Authentication Developer, Samba Team  http://samba.org
> Samba Developer, Catalyst IT
> http://catalyst.net.nz/services/samba

"If we knew what it was we were doing, it would not be called research,
would it?"
      - Albert Einstein

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