Hello,

we have had a power outage yesterday and ever since the vm is failing to start.

The logs also show this when i try to start it:

Aug 6 15:19:22 Tower kernel: BTRFS info (device loop3): first mount of filesystem 694b99d4-611d-4d7c-9e56-e1a11908d94f

Aug 6 15:19:22 Tower kernel: BTRFS info (device loop3): using crc32c (crc32c-intel) checksum algorithm

Aug 6 15:19:22 Tower kernel: BTRFS info (device loop3): using free space tree

Aug 6 15:19:22 Tower kernel: BTRFS info (device loop3): enabling ssd optimizations

Aug 6 15:19:22 Tower kernel: BTRFS error (device loop3): parent transid verify failed on logical 36880384 mirror 1 wanted 9694 found 8655

Aug 6 15:19:22 Tower kernel: BTRFS error (device loop3): parent transid verify failed on logical 36880384 mirror 2 wanted 9694 found 8655

Aug 6 15:19:22 Tower root: mount: /etc/libvirt: can't read superblock on /dev/loop3.

Aug 6 15:19:22 Tower root: dmesg(1) may have more information after failed mount system call.

Aug 6 15:19:22 Tower root: mount error

THank you in advance for the help

Here attached is my logfile:

tower-diagnostics-20250806-1409.zip

Edited August 6, 2025Aug 6 by sonicdacrack

1 hour ago, sonicdacrack said:

Aug 6 15:19:22 Tower kernel: BTRFS error (device loop3): parent transid verify failed on logical 36880384 mirror 1 wanted 9694 found 8655

Aug 6 15:19:22 Tower kernel: BTRFS error (device loop3): parent transid verify failed on logical 36880384 mirror 2 wanted 9694 found 8655

This error is fatal with btrfs, it means some writes were lost, typically due to a controller or device firmware issue. Do you have a libvirt.img backup?

No, i dont. i am backing up the vdisk at the moment. to an external drive. i als have daily backups of the vdisk on my server local.

Edited August 6, 2025Aug 6 by sonicdacrack

I recommend keeping one from now on, since it's where the VM XMLs are stored.

For now, rename that file to .bak, VM service must be stopped first, create a new one, and then recreate the VM using the same settings and pointing to the existing vdisk; that typically works.

Ok, got it. Will wait till i copied the orginal vdisk to the usb drive.

I really dont remeber how exatly the vm was setup cpus etc., will that be a issue if the setting dont match the inital setup?

The Plugin VM Backup also created xml files with the settings, ill try to recreate the same settings as the initial setup.

Could the xml file help create a libvirt.img maybe?

20250803_0200_JTL.xml

Edited August 6, 2025Aug 6 by sonicdacrack

30 minutes ago, sonicdacrack said:

Could the xml file help create a libvirt.img maybe?

Yes, you can get the settings from there.

16 hours ago, JorgeB said:

Yes, you can get the settings from there.

Thank you, got it running again. Well at least now i know that my Backups work 😅