Qubes backup restoration error reporting does not give any details

[strugee]

Qubes OS version:

R4.0

Affected component(s) or functionality:

qubes-backup-restore GUI

---

Steps to reproduce the behavior:

1. Open the "Restore Backup" application, or run it from a terminal
2. Select a backup for restore that is triggers some sort of error
3. Check the "Verify backup integrity, do not restore data" box
4. Hit next and select VMs for restore
5. Wait a few seconds

Expected or desired behavior:

The restore functionality tells me exactly what type of error occurred, at what point in the process.

Actual behavior:

The application simply shows "Finished, with errors" in red. It doesn't give any details as to what the error might have been, even on stdout.

General notes:

I'm consistently seeing these errors on a large, freshly-created backup of a single, ~350GB VM. Obviously there is some underlying bug that's causing corrupt backups to be created, which I would like to report, but I have no idea where to even start looking for this bug because the restore functionality doesn't tell me what the error was.

I put a btrfs filesystem on the drive I'm writing to specifically so I could rule out silent corruption due to the drive, and I was indeed able to successfully rule this out with a clean btrfs scrub. So the data that the restore functionality processes is definitely the data that Qubes backup produced.

---

I have consulted the following relevant documentation:

https://www.qubes-os.org/doc/backup-restore/

I am aware of the following related, non-duplicate issues:

#5393
#3498
#3216

[strugee]

Just tried to reproduce this with a smaller (<1GB) VM and could not.

[andrewdavidwong]

I'm consistently seeing these errors on a large, freshly-created backup of a single, ~350GB VM.

Just tried to reproduce this with a smaller (<1GB) VM and could not.

It has been known for a long time that large VMs are problematic for qvm-backup, while small ones are not. Possibly related issues: #5478, #5393, #4751

[marmarta]

a couple questions:
do you have enough disk space left?
is the backup in a VM or in dom0?
I'm trying to reproduce this to see when feedback gets lost

[andrewdavidwong]

In my experience, problems occur when I try to back up a large VM with compression when the data is not amenable to compression (e.g., already compressed or encrypted). In such cases, turning off compression (--no-compress) often eliminates the problem.

[strugee]

@marmarta I definitely had very little disk space left. The backup was of an AppVM, and the destination was set to an external drive attached to sys-usb. I also had compression enabled, and a lot of the VM's data was photos or compressed backups - so not particularly amenable to compression.

[marmarta]

ok, so it seems it's a genuine problem of missing disk space (for compression tmp files etc.) - and also a bug in error reporting. Will push a fix in a couple minutes :)

[qubesos-bot]

Automated announcement from builder-github

The package qubes-manager-4.1.12-1.fc32 has been pushed to the r4.1 testing repository for dom0.
To test this update, please install it with the following command:

sudo qubes-dom0-update --enablerepo=qubes-dom0-current-testing

Changes included in this update

[qubesos-bot]

Automated announcement from builder-github

The package qubes-manager_4.1.12-1 has been pushed to the r4.1 testing repository for the Debian template.
To test this update, first enable the testing repository in /etc/apt/sources.list.d/qubes-*.list by uncommenting the line containing stretch-testing (or appropriate equivalent for your template version), then use the standard update command:

sudo apt-get update && sudo apt-get dist-upgrade

Changes included in this update

[qubesos-bot]

Automated announcement from builder-github

The package qubes-manager-4.1.12-1.fc32 has been pushed to the r4.1 stable repository for dom0.
To install this update, please use the standard update command:

sudo qubes-dom0-update

Or update dom0 via Qubes Manager.

Changes included in this update

[qubesos-bot]

Automated announcement from builder-github

The package qubes-manager-4.0.44-1.fc25 has been pushed to the r4.0 testing repository for dom0.
To test this update, please install it with the following command:

sudo qubes-dom0-update --enablerepo=qubes-dom0-current-testing

Changes included in this update

[qubesos-bot]

Automated announcement from builder-github

The package qubes-manager-4.0.45-1.fc25 has been pushed to the r4.0 stable repository for dom0.
To install this update, please use the standard update command:

sudo qubes-dom0-update

Or update dom0 via Qubes Manager.

Changes included in this update