built in backup client restores mangled data. Guest doesn't start.

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rgrs

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Dec 18, 2024
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I have backups configured for all my guests in proxmox. Now for the first time I had to restore a linux server. ubuntu 24.04 thin LVM 256GB on disk. Restore task finishes OK. Start server. No disks/partitions. Why?

When start the guest it says it cant find the uuid and is dropping to abusybox shell in initramfs.

How do I recover a broken guest?
 
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What is it now ... no disks/partitions or cannot find UUID? The later means that the disk was restored and now you have an error in your guest.

Best to boot a live linux and inspect what was restored, what the UUIDs are and what it expects.

Please provide also the current PVE version installed.
 
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It can't find the specified uuid and ubuntu drops in to a busybox in initramfs. PVE version 8.4.1 I Need no solution on restoring the guest. I need to know why something trivial as backup/restore doesn't work for me. During the recovery phase I had to fix some partition errors. Steps taken to get access to the data

The system has:

/dev/sda: 64GB SSD (system disk) (bare linux that has the guest drive attached)

/dev/sdb: 256GB secondary disk (This is the drive I am trying to restore)

/dev/sdb shows a corrupt primary GPT, but a valid backup GPT exists.

Two partitions detected on /dev/sdb:

/dev/sdb1: BIOS boot (1MB)

/dev/sdb2: Linux filesystem (256GB)

Initial Mount Attempts Failed

Mounting /dev/sdb or /dev/sdb2 failed due to:

Missing device node for /dev/sdb2

Possibly bad superblock or unrecognized file system

Package Installations to recover data

Installed file, parted, and confirmed kpartx was already installed.

Recovery Steps

Used kpartx -av /dev/sdb to map GPT partitions:

Created /dev/mapper/sdb1 and /dev/mapper/sdb2

Successful Mount

Mounted /dev/mapper/sdb2 to /mnt/guest

Browsed contents successfully; includes typical Linux filesystem structure

Recovered Data

Navigated to /mnt/guest/home/user/

Found directories and files like:

apps/, guest/, updates.sh, whisper.cpp, piperdata/, webui.db, etc.

Final Result

The partition was successfully mounted using kpartx after detecting a corrupt GPT.

All intended user data under /home/user/ was accessible and appears intact.
 
rgrs said:
I need to know why something trivial as backup/restore doesn't work for me.
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I get that, but without any more information, this is hard or almost impossible to guess.

rgrs said:
During the recovery phase I had to fix some partition errors.
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Oh good, so no Linux noob. For further investigation, I suggest you do a souple of backup & restore rounds in order to see if you can replicate the problem.
There were some reports in the past about GPT corruption on the forums, yet I do not know if they relate to this problem or if they're still current problems.
 
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rgrs said:
And now what? I would really like some pointers as to why my restores fail to start.
Click to expand...
What version of Proxmox VE are you running? What backup software are you using (PBS or built-in or other)? What storage are you using (for VM/CTs and backup)? Maybe you have drive or memory corruption (did you run a memtest and long SMART test)? What hardware are you using (ECC for example)? Did you take the suggestion of running a new backup and restore on another VM/CT for testing? Maybe share the VM configuration file (before and) after a failed restore? Did you maybe exclude virtual disks from backups? Please provide some concrete information and file/configuration contents.
 
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