Ssh – Backuppc | Got fatal error during xfer (aborted by signal=PIPE)

I am running backuppc version 3.3.1 on an Ubuntu 16.04.5 LTS, I try to backup several Linux servers, almost Debian, ubuntu or proxmox hosts.

My issue is that when I run the Full/Incermental backup from webUI I got the message:

2018-08-06 14:22:32 full backup started for directory /var/lib/vz/dump/dump (baseline backup #1) 2018-08-06 14:22:33 Aborting backup up after signal PIPE 2018-08-06 14:22:34 Got fatal error during xfer (aborted by signal=PIPE) <

My backup drive is a nfs drive which is mounted as /mnt/backuppc and topdir for backuppc is /mnt/backuppc/backuppc I am able to write into it with user backuppc and/or root.

I went through several documentations and here are what I have done for debugging.

ssh -l root domain whoami root

su
su -s /bin/bash backuppc
/usr/share/backuppc/bin/BackupPC_dump -v -f HOST

gives me this output

backuppc@backup3:/home/user$ /usr/share/backuppc/bin/BackupPC_dump -v -f HOST cmdSystemOrEval: about to system /bin/ping -c 1 HOST cmdSystemOrEval: finished: got output PING HOST (149.202.75.195) 56(84) bytes of data. 64 bytes from ns3013409.ip-149-202-75.eu (149.202.75.195): icmp_seq=1 ttl=53 time=23.6 ms

— HOST ping statistics — 1 packets transmitted, 1 received, 0% packet loss, time 0ms rtt min/avg/max/mdev = 23.654/23.654/23.654/0.000 ms

cmdSystemOrEval: about to system /bin/ping -c 1 HOST cmdSystemOrEval: finished: got output PING HOST (149.202.75.195) 56(84) bytes of data. 64 bytes from ns3013409.ip-149-202-75.eu (149.202.75.195): icmp_seq=1 ttl=53 time=23.6 ms

— HOST ping statistics — 1 packets transmitted, 1 received, 0% packet loss, time 0ms rtt min/avg/max/mdev = 23.602/23.602/23.602/0.000 ms

CheckHostAlive: returning 23.602 full backup started for directory /var/lib/vz/dump/dump (baseline backup #1) started full dump, share=/var/lib/vz/dump/dump Running: /usr/bin/ssh -o ServerAliveInterval=300 -q -x -l root HOST /usr/bin/rsync –server –sender –protocol=29 –numeric-ids –perms –owner –group -D –links –hard-links –times –block-size=2048 –ignore-times . /var/lib/vz/dump/dump/ Xfer PIDs are now 2549 xferPids 2549 Got remote protocol 29 Negotiated protocol version 29 Remote[2]: skipping directory . Xfer PIDs are now 2549,2550 xferPids 2549,2550 Can't write 4 bytes to socket Read EOF: Tried again: got 0 bytes Child is aborting Done: 0 files, 0 bytes Got fatal error during xfer (aborted by signal=PIPE) Backup aborted by user signal Not saving this as a partial backup since it has fewer files than the prior one (got 0 and 0 files versus 1831) dump failed: aborted by signal=PIPE <

When I run the rsync command manually, the backup is started correctly:

rsync -av -e ssh root@HOST:/var/lib/vz/dump/dump /mnt/backuppc/backuppc/pc/pHOST/2<

Here below my HOST.pl file:
$Conf{RsyncShareName} = [
'/etc',
'/var/lib/vz/dump/dump'
];
$Conf{RsyncClientCmd} = '$sshPath -o ServerAliveInterval=300 -q -x -l root $host $rsyncPath $argList+';
$Conf{RsyncArgs} = [
'–protocol=29',
'–numeric-ids',
'–perms',
'–owner',
'–group',
'-D',
'–links',
'–hard-links',
'–times',
'–block-size=2048'
];
$Conf{ClientTimeout} = 72000;
$Conf{PingMaxMsec} = 50;
$Conf{XferMethod} = 'rsync';
$Conf{RsyncClientPath} = '/usr/bin/rsync';

I don't understand why it could log into the hosts to backup correctly and aborting immediatly after the backup start.

Can someone help me find a way out of this issue as I think I have done all the google search that could be done on this error message. Thanks a lot.

ps: Apologies for the formatting of this post, this is my first thread here and not yet familar with the syntax.