Upgrade to Qubes 4.2 - Clean Installation - Failed Restoration of VMs

User Support
1

Context: Trying to migrate:

  • from my old PC (Qubes R 4.1.2)
  • to my new PC (Ques R 4.2.4 - Clean Installation)

Steps on my old PC:
I followed https://www.qubes-os.org/doc/upgrade/4.2/, meaning I:

  1. ran the updater

  2. installd the qubes-dist-upgrade tool (sudo qubes-dom0-update -y qubes-dist-upgrade)

  3. typed this command in a dom0 terminal: qubes-dist-upgrade --template-standalone-upgrade and got:

    [user@dom0 ~]$ sudo qubes-dist-upgrade --template-standalone-upgrade
INFO: Please wait while running pre-checks...
usage: qvm-check [--verbose] [--quiet] [--help] [--all] [--exclude EXCLUDE] [--running] [--paused] [--template] [--networked] [VMNAME [VMNAME ...]]
qvm-check: error: no such domain: 'CUST0001'
WARNING: /!\ MAKE SURE YOU HAVE MADE A BACKUP OF ALL YOUR VMs AND dom0 DATA /!\
-> Launch upgrade process? [y/N] y
ERROR: Cannot continue to STAGE 4, dom0 is not R4.2 yet. Any error happened in previous stages?
[user@dom0 ~]$

    NB: I have no idea what ‘CUST0001’ is.

    I did nothing more here.

  4. backed up my VMs

Steps on my old PC:
I:

  • installed Qubes R 4.2.4

  • hit the Restore button on a Qube Manager window and gave the VMs to be restored

  • got this log on the restoration window:

    • Name of the VMs to be restored:

      -> Restoring <VM-name-1>...
-> Restoring <VM-name-2>...
-> Restoring <VM-name-3>...
...

    • Then, error messages due to eth card not being pci:03_00.0 on the new PC ==> Fine:

      Error attaching device pci:03_00.0 to <VM-on-old-PC-where-eth0-was-attached>: Invalid PCI device: 03_00.0
Error attaching device pci:03_00.0 to <other-VM-on-old-PC-where-eth0-was-attached>: Invalid PCI device: 03_00.0

    • Then, the amount of data to be restore:

      Extracting data: 289.2 GiB to restore

    • Then, after a bit of time, the same sequence of error messages for many VMs to be restored:

      Failed to restore volume root (size 21474836480) of VM <VM-NAME-X>: Cannot create new thin volume, free space in thin pool qubes_dom0/vm-pool reached threshold.
Error while processing '/home/user/QubesIncoming/backup#restore-wmmuzuqu/vm51/root.img.000': 
ERROR: unable to extract files for /home/user/QubesIncoming/backup#restore-wmmuzuqu/vm51/root.img.000, tar output: 
Failed to restore volume private (size 5368709120) of VM <VM-NAME-X>: Cannot create new thin volume, free space in thin pool qubes_dom0/vm-pool reached threshold.
Error while processing '/home/user/QubesIncoming/backup#restore-wmmuzuqu/vm51/private.img.000': 
ERROR: unable to extract files for /home/user/QubesIncoming/backup#restore-wmmuzuqu/vm51/private.img.000, tar output:

    • Then, the closing:

      Restoring home of user 'user' to 'home-restore-2025-06-17-191920' directory...
-> Done.
-> Please install updates for all the restored templates.
Finished successfully!

Additional info:

  1. On my new PC, I dedicated 900 GiB to Qubes, which is more than on my old PC

  2. df -h on dom0, after the (unsuccessfull) installation:

    Filesystem                   Size  Used Avail Use% Mounted on
devtmpfs                     4.0M     0  4.0M   0% /dev
tmpfs                        2.0G   24K  2.0G   1% /dev/shm
tmpfs                        779M  2.3M  777M   1% /run
efivarfs                      64K   34K   25K  58% /sys/firmware/efi/efivars
/dev/mapper/qubes_dom0-root  885G  6.8G  834G   1% /
tmpfs                        2.0G   44K  2.0G   1% /tmp
/dev/nvme1n1p2               974M  138M  769M  16% /boot
/dev/nvme1n1p1               599M   32M  568M   6% /boot/efi
tmpfs                        390M  112K  390M   1% /run/user/1000

  3. Afterwards, I installed Qubes R 4.2.4 again from scratch and I tried to restore only 2 VMs (a VM and it’s template). I did not get any error message and the restoration of both VMs looks OK at first sight.

  4. Afterwards, I went on and tried to restore 15 VMs at the same time ==> I got the error messages

    During that restoration, every time I looked, /dev/mapper/qubes_dom0-root’s use was always <= 5% (obviously, I was not constantly watching)

  5. New PC is Qubes certified

Questions:

  • Why all those error messages when I try to restore all of the VMs at the same time
  • What should I do to be able to restore all of my VMs in one batch?
2

I started over with a new R4.2.4 installation on the new laptop.

Just after a brand new installation, I have on dom0:

[user@dom0 ~]$ sudo lvs | grep "twi"
  root-pool           qubes_dom0 twi-aotz-- 900.00g      2.30   1.48
  vm-pool             qubes_dom0 twi-aotz-- <89.81g      18.30  16.77
[user@dom0 ~]$

On my old laptop (with many VMs), I currently have:

[user@dom0 ~]$ sudo lvs | grep "twi"
  root-pool           qubes_dom0 twi-aotz--  49.77g      18.44  17.69 
  vm-pool             qubes_dom0 twi-aotz-- 664.62g      72.15  55.21                         
[user@dom0 ~]$

When I restore one VM at a time on the new laptop, I have no problem with the first ones. But after 10 VMs or so, I get the same error message as always: vm-pool reached threshold. Indeed, when I click on the hard drive icon in the system tray, I see that vm-pool is at >90%.

Questions:

  • Is it vm-pool that should contain all VMs? If so, how come vm-pool is so small after a new install on my new laptop?

  • During the install, I requested 900 GiB on / so I understand where that value come from. But where does “<89.81g” come from?

  • During the install, there is a “Advanced Configuration” section that propose:

    • “Use existing LVM thin pool” instead of the default
    • “Create ‘vm-pool’ LVM thin pool”.

    Is this part of my problem? Should I go for an advanced non-default configuration? Looks odd.

  • What should I do to restore more than ten (or so) VMs on the new laptop?

Thanks!