Each file produces the following error in the log:
ERROR: Error getting internal id for user with id XXXXXX
ERROR: Error getting internal id for group with id YYYYYY
These are the current accounts of the owners of the files in Active Directory.
This overflows the log and significantly slows down the progress of the backup. Especially the copying of METADATA
Centos 6 + Samba 3.6.23 + winbind + urbackup client 2.1.16