Snapshot failing with qmp command 'blockdev-snapshot-internal-sync' failed - Need a root block node for some VMs

[GM2024]

Hello,

I'm trying to figure out why some of our VMs won't snapshot successfully. It's working for half of them; the only difference that I can see between those that snapshot and those that won't is that the HD is a bit bigger (160gb vs. 80gb), but that's it...

Full output:

snapshotting 'drive-scsi0' (local:100/base-100-disk-0.qcow2/101/vm-101-disk-0.qcow2)
snapshot create failed: starting cleanup
TASK ERROR: VM 101 qmp command 'blockdev-snapshot-internal-sync' failed - Need a root block node

Any suggestion how we can troubleshoot this?

 

[fiona]

Hi,
that likely means some other operation didn't clean up properly. Please share the output of pveversion -v, qm config 101 and the output of the following script

root@pve8a1 ~ # cat query-block.pm

#!/bin/perl

use strict;
use warnings;

use JSON;

use PVE::QemuServer::Monitor qw(mon_cmd);

my $vmid = shift or die "need to specify vmid\n";

my $res = eval { mon_cmd($vmid, "query-block" ) };
die $@ if $@;
print to_json($res, { pretty => 1, canonical => 1 });

You can run it with perl query-block.pm 101.

EDIT: Shutting down+starting the VM (or using the Reboot button in the UI, reboot in the guest is not enough) or live-migrating it to a different node, means that there will be a new QEMU instance running the VM, so the issue should go away then.