[Samba] Use 4.10 backup in 4.9.4

[Tim Beale]

Hi Viktor,

In 4.10.0, the fix for https://bugzilla.samba.org/show_bug.cgi?id=13760
will take effect when the samba process first starts. In theory, if you
take a backup after this, that backup database should no longer have bug
13760 in it.

It seems like what you're seeing might be a different problem. If
samba_dnsupdate isn't working, then DNS may well not work. And if DNS
isn't working, then auth probably won't either. So you might be seeing
the same symptoms for a different reason.

If you're using bind_dlz, then 4.10 does have bug 13841 in it.
Otherwise, it might be worth double-checking the smb.conf and
/etc/resolv.conf settings after the restore to make sure they're correct.

Cheers,
Tim

On 31/03/19 4:44 AM, Viktor Trojanovic via samba wrote:
> I'd like to share the results of a little experiment I did yesterday.
>
> On an Arch Linux box on which in December I tried, and failed, to upgrade
> from 4.7.4. to 4.9.4 and then had to revert back to 4.7.4, yesterday I did
> the upgrade to the new 4.10 release. This time, everything worked, I had no
> errors whatsoever. So, I then made a backup of the new installation, in 3
> different ways: Online backup, offline backup, and simple file backup of
> the whole Samba folder including smb.conf.
>
> Then, I had to move the backup to a new box running Ubuntu 18.04. The
> latest available release there, currently, is still 4.9.4. from Louis'
> repo. I was under the assumption that now that 4.10 took care of the
> errors, it should be possible to just use the same data in 4.9.4, all I'd
> lose were certain functions and fixes.
>
> That was clearly too optimistic. Restoring the backup on 4.9.4, in no
> matter which way, would lead to the exact same result I used to have when I
> tried to upgrade from 4.7.4. to 4.9.4 directly. Samba starts fine, at
> first, but samba_dnsupdate breaks with an error 110. DNS and authentication
> don't work. As advised in the bug report, I tried running ldbedit on
> private/sam.ldb, I did an index rebuild, all without issues but also
> without effect on the error.
>
> Since I need this to work on Bionic, I ended up installing the default
> package 4.7.4 and just copied (preserving all attributes) the entire samba
> folder from the previous installation, and it works again. No error
> messages in the log whatsoever.
>
> I solved this situation for now and have no urgency to find out more about
> it but I do wonder, did 4.10 not actually correct the data issue in such a
> way that 4.9.4. should have been able to use it?
>
> - Viktor