[Samba] CTDB and PDC Role

[Volker Lendecke]

On Tue, Nov 02, 2010 at 06:48:38PM +0000, Alex Crow wrote:
> I asked a question like this ages ago:
> 
> If you had a shared filesystem between the PDC and BDC(s) then
> surely you wouldn't need to migrate your BDC to a PDC automatically,
> you could do it at your leisure.

Well, depending on your passdb backend this might or might
not work. I would not count on file system failover to get
the passdb.tdb right in all cases. Probably I am too
paranoid here, as we're using proper tdb transactions these
days, but between a CPU and a disk spindle in a SAN setup
too much can go wrong for my taste.

The main difference between a PDC and a BDC in a Samba setup
is the "domain master = yes/no". It is really just a matter
of setting that to yes and a restart of smbd and nmbd to
promote a BDC to a PDC.

> For your logon scripts and profiles in your LDAP you'd just point to
> a virtual IP/hostname of the PDC/BDC cluster.
> 
> Volker, would this work?

Details pending, the general idea sounds okay. But please be
aware that in HA setups so much can go wrong that it's not
funny anymore. The devil is really in the details.

Volker