[Samba] fail-over, redundancy, bdc, multi-dc-domain

[Gregory Sloop]

I'm aware of, at least generally, how one would have done a
BDC/Redundant server under OpenLDAP Samba3.

However, rolling your own multi-domain-controller was fairly daunting
[for me] under Samba3 / OpenLDAP.

I've been very interested in Samba4 for the more integrated nature of
having LDAP/DNS/Samba all under one roof. [i.e. Fewer places where I
can screw it up horribly.]

However I'm also interested in how one can handle fail-over. I don't
need something totally seamless and "big-iron" style. A backup box
that would need some manual intervention would be fine.

So, something like an rsync'd backup box where the shared
files/accounts/etc are perhaps an hour out of date, and that would
require 15 minutes to bring up as a primary would be an acceptable
solution.

That's not to say I wouldn't want something better, but that's kind of
the low end of the "acceptable" scale.

I've done some searches on the list and spent a while looking for
"examples" but I don't easily find any. [Using searches with: samba4 bdc,
redundant, backup, etc. There are a ton of very old articles on the
list, but almost nothing I could find specifically on Samba4.]

Could some kind soul point me either to:
1) Search terms more likely to produce results, or some discussion threads or
2) wiki/how-to's on how to accomplish something in the neighborhood on this subjet?

[Option #2 preferred.]

As a note, I'd be glad to help document this/provide a "here's what I
did and how", provided it's something reasonable for me to apply to
the situation I'm referring to - so I'm more than glad to contribute
back where I can.

TIA
-Greg