@olivierlambert
I run the same task all the time without any changes.
How is it determined that the task must be run as full or as a delta?

@olivierlambert
I was able to reproduce the problem on the lastest XOA server.
Give this id to the Support tunnel : 41699

Backup Task settings:

XOA work correct if vCPU settings are 1socket= 1 core

If I change vCPU to 1 socket = 2 cores or 1socket= 4 core

Received error when starting the same task

@olivierlambert
"Expected values to be strictly equal: 430 !== 512" is not the result of using a GFS2 drive.
On an XOA (non-source) server, the delta backup on the GFS2 drive completed with a successful result

Clarification
During the backup process, I can edit and crate Backup tasks, only to display information about VMs and SRs I need to wait about 5 minutes.

@julien-f @olivierlambert
The support tunnel has been created.

Do not stop this command before the intervention is over!
Give this id to the support: 41699

@olivierlambert
[06:08 15] xoa@xoa:~$ ping tunnel.xen-orchestra.com
PING shelter.vates.fr (159.69.135.93) 56(84) bytes of data.

@olivierlambert
According to information from proxy admins, the XOA server does not connect to the proxy during the creation of the support tunnel.
The netstat command showed that the server is creating a NAT connection.
tcp 0 1 10.44.71.176:43312 159.69.135.93:443 SYN_SENT

This means that the Support tunnel does not use proxy settings.

@olivierlambert
add tunnel.xen-orchestra.com 159.69.135.93 to /etc/resolv.conf and /etc/hosts

But error exist
Warning: Failing to resolve tunnel.xen-orchestra.com, falling back to 212.129.28.35

Update - OK

@olivierlambert
Proxy settings are already persists on the Updates tab

@olivierlambert
Server XOA behind the proxy

@olivierlambert
Installed a trial version of XOA from the latest channel.
The problem persists.