[Samba] samba 3 to samba 4 migration questions

[Chris Smith]

Hello,

I need to move the DC properties of an existing Samba 3 server (PDC as
well as file and print services) to a new Samba 4 AD, while keeping
the other capabilities (file and print services) intact on the
existing Samba 3 system.

In some preliminary testing I attempted to follow the "Upgrading on a
New Server" section of the classic upgrade howto, however, none of the
current users or machines were picked up. I'm guessing at this point
that the instructions left out that the underlying Linux users and
groups need to be transferred (re-created) previous to attempting said
migration. Or am I overlooking something else?

After (hopefully) successfully moving the DC duties I still need the
file and print services to continue for some time on the old server,
which will now have to authenticate the users via the new AD. How does
this affect the now local users and groups re-created on the new AD?
Should the local users be removed and the UID/GID's manually
reassigned to whatever Winbind (or another service such as SSSD)
provides?

I'm just not clear on the best way to go about this. Thanks for any assistance.

Chris