You do not enable NBD in your VM, you enable NBD on a XCP-ng network, that's it.

There's no drawback to enable it (well, it's a new service exposed but it's OK)

@Gheppy

I would have done those operation, if i wouldn't loose connection to xcp-ng.
I got only 1 IP address which is dedicated to pfsense, and from there i connect to xcp-ng (LAN side).

Hi,

sorry for the long break. i'll continue here for my colleague AlexD2006.

We have now also tried with the current version (deeb3) of Xen-Orchestra, the problem remains the same. But we have now noticed other error messages (also with the old version) that appear during a delta backup ("base VDI is not a vhd; cannot compute differences"):

May 23 16:40:35 xcp-mono02 xapi: [error||7644621 HTTPS 10.32.1.159->:::80|[XO] Exporting content of VDI test-vm.test 1 R:2e892fda7776|vhd_tool_wrapper] base VDI is not a vhd; cannot compute differences May 23 16:40:37 xcp-mono02 xapi: [error||7644621 :::80||backtrace] [XO] Exporting content of VDI test-vm.test 1 R:2e892fda7776 failed with exception (Failure "base VDI is not a vhd; cannot compute differences") May 23 16:40:37 xcp-mono02 xapi: [error||7644621 :::80||backtrace] Raised (Failure "base VDI is not a vhd; cannot compute differences") May 23 16:40:37 xcp-mono02 xapi: [error||7644621 :::80||backtrace] 1/14 xapi Raised at file stdlib.ml, line 29 May 23 16:40:37 xcp-mono02 xapi: [error||7644621 :::80||backtrace] 2/14 xapi Called from file ocaml/xapi/vhd_tool_wrapper.ml, line 206 May 23 16:40:37 xcp-mono02 xapi: [error||7644621 :::80||backtrace] 3/14 xapi Called from file ocaml/xapi/export_raw_vdi.ml, line 50 May 23 16:40:37 xcp-mono02 xapi: [error||7644621 :::80||backtrace] 4/14 xapi Called from file lib/xapi-stdext-pervasives/pervasiveext.ml, line 24 May 23 16:40:37 xcp-mono02 xapi: [error||7644621 :::80||backtrace] 5/14 xapi Called from file lib/xapi-stdext-pervasives/pervasiveext.ml, line 35 May 23 16:40:37 xcp-mono02 xapi: [error||7644621 :::80||backtrace] 6/14 xapi Called from file lib/xapi-stdext-pervasives/pervasiveext.ml, line 24 May 23 16:40:37 xcp-mono02 xapi: [error||7644621 :::80||backtrace] 7/14 xapi Called from file lib/xapi-stdext-pervasives/pervasiveext.ml, line 35 May 23 16:40:37 xcp-mono02 xapi: [error||7644621 :::80||backtrace] 8/14 xapi Called from file ocaml/xapi/export_raw_vdi.ml, line 90 May 23 16:40:37 xcp-mono02 xapi: [error||7644621 :::80||backtrace] 9/14 xapi Called from file ocaml/xapi/export_raw_vdi.ml, line 116 May 23 16:40:37 xcp-mono02 xapi: [error||7644621 :::80||backtrace] 10/14 xapi Called from file ocaml/xapi/server_helpers.ml, line 101 May 23 16:40:37 xcp-mono02 xapi: [error||7644621 :::80||backtrace] 11/14 xapi Called from file ocaml/xapi/server_helpers.ml, line 122 May 23 16:40:37 xcp-mono02 xapi: [error||7644621 :::80||backtrace] 12/14 xapi Called from file lib/xapi-stdext-pervasives/pervasiveext.ml, line 24 May 23 16:40:37 xcp-mono02 xapi: [error||7644621 :::80||backtrace] 13/14 xapi Called from file string.ml, line 115 May 23 16:40:37 xcp-mono02 xapi: [error||7644621 :::80||backtrace] 14/14 xapi Called from file src/sexp.ml, line 113 May 23 16:40:37 xcp-mono02 xapi: [error||7644621 :::80||backtrace]

Can anyone say anything about the cause of the problem or any ideas for further analysis?

It is very simple. Whatever happens to your system, you can re-import your previous metadata on a fresh system and everything will be back on track as it were before the issue.

@Darkbeldin Done. Thanks for the reply. It took a while to make sure I was understanding it, but I think I've got the hang of it now.

@olivierlambert Thank you for following up.

Not yet, it's not top priority until we got our new backup code ready. After that, it might be easier than before 🙂