Some end user tests with LMDB branch

[Andrew Bartlett]

On Fri, 2018-05-11 at 11:52 +0200, Denis Cardon wrote:
> G'day Garming, Andrew 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!

> 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.  

> 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
-- 
Andrew Bartlett                       http://samba.org/~abartlet/
Authentication Developer, Samba Team  http://samba.org
Samba Developer, Catalyst IT          http://catalyst.net.nz/services/samba