[Samba] Replace AD DC FS with 2 new servers
rpenny at samba.org
Mon Nov 26 17:08:32 UTC 2018
On Mon, 26 Nov 2018 17:27:29 +0100
Mark Amundsen via samba <samba at lists.samba.org> wrote:
> > >
> > > Is 'idmap rid' a better choice than ad? Can I still copy files
> > > with rsync in that case or will file ownership be mangled?
> > Quantify better ?
> > One isn't really better than the other, they are both usable, but in
> > different ways and reasons.
> > It might help if you read this:
> > https://wiki.samba.org/index.php/Setting_up_Samba_as_a_Domain_Member
> I've read it several times, but i start to think that I simply don't
> understand the concepts.
The concepts are fairly simple, you only need uidNumber & gidNumber
attributes in AD if you want the same numeric ID's everywhere.
DC's use xidNumber attributes and these are only used on a DC.
You can use either the 'ad' or 'rid' backend on a Unix domain member
and only on a Unix domain member.
> The old server does not have idmap config in the smb.conf (because it
> is a DC, right?).
You cannot use the 'idmap config' lines on a DC.
> If I ls a file in the old fileserver, it looks like this:
> -rwxrwx---+ 1 3000148 users 31M sep 19 15:16 10160-101.zip
> So, 3000248 is a UID.
To be honest, it looks like an 'xidNumber', the '3000000' numbers
normally only occur on a Samba AD DC, was the old fileserver a DC ?
> If I use winbind 'rid' backend and copy the file above to the new
> server with rsync it will keep 3000148 as owner, but will 3000148 be
> connected to the same login on both servers?
Not necessarily, as I said, '3000148' looks like an xidNumber from
idmap.ldb and, as is well known, you probably would get a different
number on another DC, the same will go for a Unix domain member using
the 'rid' backend.
The users UID on a Unix domain member using the 'rid' backend is
calculated from the users 'RID' with this equation:
ID = RID - BASE_RID + LOW_RANGE_ID
All RID's start from '1000' and the BASE_RID is '0' unless set to a
different number, so, from this and the info provided below, the
equation could be written as this:
ID = RID + 3000000
And using the lowest RID
ID = 1000 + 3000000
ID = 3001000
So, no, you will never see the ID '3000148' on a Unix domain member
> I think that I'll just add a testserver to find out how it works.
> security = ADS
> workgroup = SAMDOM
> realm = SAMDOM.EXAMPLE.COM
> log file = /var/log/samba/%m.log
> log level = 1
> idmap config * : backend = tdb
> idmap config * : range = 3000-7999
> idmap config SAMDOM : backend = rid
> idmap config SAMDOM : range = 3000000-3999999
> Will that do (but replace SAMDOM with my realm)?
Yes, but just as long as you understand that you will never get the
same numeric ID's everywhere.
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