[Samba] classicupgrade migration issues

[Sonic]

On Fri, Mar 18, 2016 at 2:39 PM, Andrew Bartlett <abartlet at samba.org> wrote:
> Exactly.  Think about it a little - how can it determine the group
> membership, if the users/groups do not exist locally on the host doing
> the migration?

To clarify then:
Do I need both the users and groups on the new host as they are on the
old host, or just the groups? Is there any constraint that the GID's
and or UID's need to be the same on the new host?
Once the migration is done can I then remove the added 'nix groups
and/or users with no ill effects?

Thank you,

Chris