Some end user tests with LMDB branch

Denis Cardon dcardon at
Sat May 12 14:44:15 UTC 2018

G'day Andrew, Garming and all,
>>> 0x000021bf is known as WERR_DS_DRA_RECYCLED_TARGET
>>> This might actually be expected behaviour (assuming the join still
>>> proceeded despite the error). There is a back-off if it discovers that
>>> there is a missing link, then it retries with the GET_TGT flag (which
>>> Tim implemented for 4.8) -- this used to cause serious problems with
>>> Windows joins.
>> ok, everything is fine after the join, so I assume it was the issue you
>> outlined, as the other server is still a 4.7.7 (actually we haven't
>> started 4.8 upgrades, waiting for Andrew's in place upgrade patch to
>> make it in the next 4.8 minor release).
>> Doing a little more testing, ldapcmp is happy comparing between a 4.7.7
>> and LMDB branch, and everything is fine. By the way, the test is done on
>> small, but real world database copy with about two years of
>> living/upgrading.
> Thanks!

I went forward this afternoon with an Samba LMDB installation on a non 
critical network (small primary school). This domain is quite small (one 
DC, one site, a dozen user accounts and two dozen computer accounts), 
but it is a real one, and it has lived for the last 6 years and been 
upgraded every 6 months (since Samba 4.0.0 alpha18 actually :-).

As we discussed earlier, I have kept a 4.7 DC replicating the LMDB DC in 
case I need to revert quickly. That second DC is firewalled so it can 
only do replication with LMDB DC and cannot be contacted by any other 

>> For the tooling, is there something like ldbsearch for querying lmdb
>> files, or we just have to query using ldbsearch on sam.ldb file itself
>> (which is working properly by the way)?
> ldbsearch with mdb:// or ldb:// as the prefix is what you need to do.

Works perfectly, thanks!

By the way, the handling of DNS entry creation during DC join is much 
better than it used to be. It makes replication working almost 
instantly. Samba is really getting too simple to install, I'm afraid I'm 
going to get out of business if it gets that easy ;-)



>> If all the testing goes well, I am thinking about upgrading one small
>> primary school on LMDB to get live feedback. What would be the rollback
>> procedure to go back to a 4.8 tdb database if needed? Since the database
>> format is completly different, I guess it won't be as easy as the 4.8 to
>> 4.7 GUID index fixing. I was thinking about keeping a firewalled Samba
>> 4.8 replicating with Samba LMDB, and switching the two (or a backup of
>> the 4.8 instance) if needed. Do you have better ideas?
> ldbdump has been taught about the mdb file format, so the backend files
> can be re-constructed by dumping each one, rebuilding as raw tdb then
> re-connecting to the sam.ldb.  However as there isn't an auto-upgrade
> I've not provided an auto-downgrade.  In general it is better to do
> these things over DRS replication (ie a join as you have done).
> Thank you so much for giving this a go!
> Andrew Bartlett

Denis Cardon
Tranquil IT Systems
Les Espaces Jules Verne, bâtiment A
12 avenue Jules Verne
44230 Saint SĂ©bastien sur Loire
tel : +33 (0)

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