Backup via RAW copy-on-write image does not work

general discussion
1

Can not determine what the problem is in the client or the server?

Configured zfs in accordance with the documentation
urbacku-server is started from root

When choosing RAW copy-on-write i was get error:

Server Ubuntu 16.04
Client Windows 2.1.16

root@plt-backup:~# apt show urbackup-server
Package: urbackup-server
Version: 2.1.19.1765-1ubuntu1~xenial

root@plt-backup:~# cat /etc/default/urbackupsrv 
# Defaults for urbackupsrv initscript
# sourced by /etc/init.d/urbackupsrv and /lib/systemd/system/urbackup-server.service
# installed at /etc/default/urbackupsrv by the maintainer scripts
#
# This is parsed as a key=value file
#
FASTCGI_PORT=55413
HTTP_SERVER="true"
HTTP_PORT=55414
LOGFILE="/var/log/urbackup.log"
LOGLEVEL="warn"
DAEMON_TMPDIR="/tmp"
SQLITE_TMPDIR=""
BROADCAST_INTERFACES=""
USER="root"

cat /etc/urbackup/backupfolder 
/mnt/services/SYSTEM/urbackup

cat /etc/urbackup/dataset 
hdd/local/SYS/urbackup

root@plt-backup:~# zfs list -r hdd/local/SYS/urbackup
NAME                                                  USED  AVAIL  REFER  MOUNTPOINT
hdd/local/SYS/urbackup                               5,06G   624G  5,06G  /mnt/services/SYSTEM/urbackup
hdd/local/SYS/urbackup/alexandriya-wycon-nebo-kassa    96K   624G    96K          /mnt/services/SYSTEM/urbackup/alexandriya-wycon-nebo-kassa

/var/log/urbackup.log
2017-11-01 03:07:30: ERROR: Backing up System Reserved (SYSVOL) partition failed. Image backup failed
2017-11-01 03:07:30: ERROR: Backup failed

In client log
Starting scheduled full image backup of volume “C:”…
Backing up System Reserved (SYSVOL) partition failed. Image backup failed
Time taken for backing up client alexandriya-wycon-nebo-kassa:
Backup failed

root@plt-backup:~# urbackup_snapshot_helper test
Testing for btrfs...
ERROR: not a btrfs filesystem: /mnt/services/SYSTEM/urbackup/testA54hj5luZtlorr494
TEST FAILED: Creating test btrfs subvolume failed
Testing for zfs...
ZFS TEST OK

I have no idea what else to check

2

back up via VHD work fine

3

Did you start the server as root? (urbackupsrv run -u root ?)

4

Yes, the urbackup process is started from the user “root”.

root@plt-backup:~# ps aux | grep urbackup
root     48604  0.0  0.0  15472   984 pts/1    S+   19:19   0:00 grep --color=auto urbackup
root     52300  4.3  0.4 2334300 70112 ?       Sl   03:10  41:55 /usr/bin/urbackupsrv run --config /etc/default/urbackupsrv --daemon --pidfile /var/run/urbackupsrv.pid

Moreover, apparently, urbackup could even create an appropriate dataset.

root@plt-backup:~# zfs list -r hdd/local/SYS/urbackup -t all -o name
NAME
hdd/local/SYS/urbackup
hdd/local/SYS/urbackup/alexandriya-wycon-nebo-kassa   <---This one

I got the impression that the reason is in the client. But how to carry out the diagnosis? In favor of this version, it says that in the client’s logs an error appears after trying to make a copy of the SYSVOL section

Sorry for my bad English

5

Some users had problems because there is a length limit for the datasets, so try to keep those small by using a small pool name (e.g. a single name a) and dataset name. You can also make the client name smaller by renaming it.