Final results (client with defect sectors):
- download of full backup as zip does not work, if a certain amount of files is exceeded
- in my special case I could not perform a restore on the client to a mounted drive, because:
2017-12-01 22:51:24: ERROR: Cannot read file metadata of file /mnt/urbackup/RaspberryPi1/171201-2032/root from /mnt/urbackup/RaspberryPi1/171201-2032/.hashes/root/.dir_metadata. Cannot start restore. - I have deleted all backups and made a new full backup via server, excluding the directory which was affected by the
defect sectors - I powered off the client. Then downloaded the client-install from server and installed the client on my notebook
- with this client I restored the backup and the copied it to a new disk
- finally the initial client is up and running again with a new disk
I know, quite complicated, but I wanted to use urbackup to learn, how it works.
Finally many thanks to uroni and orogor who help me very much 