Status of BTRFS Support

indolering · February 22, 2023, 4:11am

I have been trying to figure out what the status of BTRFS support is on Qubes. There are a lot of forums posts reporting increased performance and I was able to install the latest RC with BTRFS instead of LLVM thin provisioning. However, it is not the default and many tickets referencing it have been assigned TBD milestones.

I installed it and it seems to be working fine. Is it going to blow up on me? What are the sharp edges?

renehoj · February 22, 2023, 6:24am

I have been using it for 3-4 months now, I have not had any issues.

There is a difference in how disk size is displayed in applications like qubes manager and backup tool, with btrfs they show the size of vm + template with ext4 it’s just the vm, but it doesn’t make any practical difference.

kommuni · February 22, 2023, 7:32am

The only problems I have experienced is related to restoring backups.

github.com/QubesOS/qubes-issues

Restore failure - Unexpected EOF - retrieved data backup size exceed expected size

opened 02:47AM - 12 Jan 22 UTC

m4teh

T: bug C: core P: major diagnosed

### Qubes OS release 4.1.0-rc3 ### Brief summary Sporadic but majority fail…ed restores (or corrupted backups) on 4.1x installations. Any size backup, small or large. Using Btrfs. Restoring on same version of Qubes, same and different systems. Will restore AppVM but contain no data. Will display an error but conclude with "Finished successfully!", when it has not. Only one reference to the same issue from 2017 found here https://groups.google.com/g/qubes-users/c/0i7RfWhoCxU Backups and data do appear to restore successfully if running **qvm-backup-restore --ignore-size-limit** via dom0. Forum issue discussion here - https://forum.qubes-os.org/t/backups-are-corrupted-on-restore/8446 ### Steps to reproduce Create a backup and restore it. ### Expected behavior Successful restore containing all data with no errors. ### Actual behavior Restores empty AppVM containing no data, and errors contained in the output. Unable to extract files, unexpected EOF in archive tar, retrieved data backup size exceed expected size ![7d496c01e2ff654edaf628a888af6336f19ed590](https://user-images.githubusercontent.com/13673512/149054440-09f01276-51bb-4dce-badd-9c0f24ca30d8.jpeg)

indolering · February 22, 2023, 10:27pm

Sounds like this also happens in EXT4? And the qvm-backup-restore --ignore-size-limit workaround fixes it?

kommuni · March 6, 2023, 12:20am

Yes, that workaround works.