The script samba_backup simply tars the tdb files, should use tdbbackup.
It does use tdbbackup for ldb files, but not for tdb.
A patch was posted in the mailing list, but apparently not included
Also I wonder if it is save to not backup the contents of LOCKDIR.
Older descriptions say that this must be backed up as well.
Closing bug report, the script in the report has been superseded by the later python script, so this bug report is no longer relevant.