Restored Backups Do Not Boot

creoleMalady

I have both Delta backups and full backups failing to restore properly from an NFS source. I have them throwing into a UEFI rescue mode. I have Debian Buster images doing this and Centos 8 with xo-server 5.81.2 and XCP-NG 8.2.0.

My original VM's are using Secure Boot with UEFI, I have learned that secure boot isnt supported by XCP-NG, and I have not tested non-UEFI VM's and their backups

I do not know what I am missing, nothing about the restore fails, they just will not boot.

olivierlambert

First, you need to check if it's a guest issue or not. Boot your failed restored VM with a live CD (Ubuntu or something else) and check if you can access the disks.

creoleMalady

@olivierlambert

I got a VM to boot into an Ubuntu live CD and could see the disk and its respective partitions, and LVM setup.

olivierlambert

So you can access all data? Have you try to chroot in it, check grub?

creoleMalady

@olivierlambert so I booted into Finnix, and was able to mount the root LVM and verify that the filesystem is intact and the files I expect to see are all there. The chroot environment is functional and I don't see anything worry about.

I was able to mount and rebuild the /boot through efi/EFI paths, I have not yet bothered checking file hashes or anything forensic, but I am seeing all the contents in the backups that I see in the running VM from which this backup originated.

One thing I have found, is that only deltas are failing to restore in bootable form. Full backups are fine. I tried to restore the periodic full snapshots within the delta cycles, but those aren't any better than restoring a later delta.

I will be switching to full backups only until I know why delta is broken in my environment.

olivierlambert

That's weird, you are the first one to report this, so I wonder what's different in your environment

creoleMalady

@olivierlambert I have swapped to normal full backups for now.

I have non-emergency need to recover at least one VM and have a couple options on how to do so since the data appears intact.

In all fairness to xcp-ng, the hardware we use is a mix of older machines (it is not a funded enterprise setup). I would be willing to provide your team specific hardware details among other things but I will be slow to gather info.

I will try out a delta backup of a bios VM as soon as I find the time. My only theory, which I have little evidence or ability to test, is that I have triggered a bug in the uefi firmware used by the VM. I can at least narrow down a bit more by comparing uefi versus legacy.

olivierlambert

Sure, please keep us posted on your experiments If it's a bug, we'll have more info to be able to work on it!