samba/sme10/README.downgrade

Downgrading Samba
=================

Short version: data-preserving downgrades between Samba versions are not supported

Long version:
With Samba development there are cases when on-disk database format evolves.
In general, Samba Team attempts to maintain forward compatibility and
automatically upgrade databases during runtime when requires.
However, when downgrade is required Samba will not perform downgrade to
existing databases. It may be impossible if new features that caused database
upgrade are in use. Thus, one needs to consider a downgrade procedure before
actually downgrading Samba setup.

Please always perform back up prior both upgrading and downgrading across major
version changes. Restoring database files is easiest and simplest way to get to
previously working setup.

Easiest way to downgrade is to remove all created databases and start from scratch.
This means losing all authentication and domain relationship data, as well as
user databases (in case of tdb storage), printers, registry settings, and winbindd
caches.

Remove databases in following locations:
/var/lib/samba/*.tdb
/var/lib/samba/private/*.tdb

In particular, registry settings are known to prevent running downgraded versions
(Samba 4 to Samba 3) as registry format has changed between Samba 3 and Samba 4.
1	Downgrading Samba
2	=================
3
4	Short version: data-preserving downgrades between Samba versions are not supported
5
6	Long version:
7	With Samba development there are cases when on-disk database format evolves.
8	In general, Samba Team attempts to maintain forward compatibility and
9	automatically upgrade databases during runtime when requires.
10	However, when downgrade is required Samba will not perform downgrade to
11	existing databases. It may be impossible if new features that caused database
12	upgrade are in use. Thus, one needs to consider a downgrade procedure before
13	actually downgrading Samba setup.
14
15	Please always perform back up prior both upgrading and downgrading across major
16	version changes. Restoring database files is easiest and simplest way to get to
17	previously working setup.
18
19	Easiest way to downgrade is to remove all created databases and start from scratch.
20	This means losing all authentication and domain relationship data, as well as
21	user databases (in case of tdb storage), printers, registry settings, and winbindd
22	caches.
23
24	Remove databases in following locations:
25	/var/lib/samba/*.tdb
26	/var/lib/samba/private/*.tdb
27
28	In particular, registry settings are known to prevent running downgraded versions
29	(Samba 4 to Samba 3) as registry format has changed between Samba 3 and Samba 4.