VM crashed. possible to restore certain harddisk?

[fraksken]

Hello,

One of my (more important) VM's just crashed.
The VM has 3 disks attached: 2 data disks and 1 OS disk.
The OS disk seems corrupt.
The last backup is from 5 days ago. I would only need to restore the OS disk.
How can I achieve this?
Last version of proxmox.

For incidents as this I would welcome a paid support option.

I would also love features like detach harddrives and attach them to other systems

 

[fraksken]

I'm trying to follow the following guide to move a disk from a recovered system to the faulty vm:
https://pve.proxmox.com/wiki/Moving_disk_image_from_one_KVM_machine_to_another
however, I only get to see the data lv:
root@host:/home/# lvs -o +lv_tags
LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert LV Tags
data pve -wi-ao---- 2.71t

What could i be doing wrong?

 

[fraksken]

ok. so for some reason, I don't know how or why, but since the last boot of that server (53 days) the partition table of the bootable disk disappeared. Resulting in all my other backups to be faulty also.

Luckily I had the foresight of making a backup of the completed VM some time ago. I managed to boot that system and extract the partition table.
In rescue mode I was able to replace the partition table, but the disk still did not want to boot.
(Hangs at "Booting from Hard Disk")

I did manage to mount the partitions in rescue mode. So now, my next step will be to make a backup, boot the system to rescue mode and dd all but the boot partition. see if that works.

 

[fraksken]

Just for reference,
The dd-ing did not work.
Next best solution was to create a new harddrive, mount them both on a VM and use cp -furp or rsync to move all the required data from one to the other disk.

 

[Enrico90]

Hello, I am having similar problems with machine with partition table disappeared.
Did you find a way to fix it? what version of proxmox are you using?

 

[fraksken]

Enrico90 Yes, I did solve my problem.
I was using the most recent version of Proxmox at that time as it is being updated automatically on my servers.
Can you describe your situation?

In the meantime I'll try to recollect the things I've done and steps I've taken.

 

[Enrico90]

Yes, I have a debian VM inside a proxmox 4.2 machine.
Today I shut it off to upgrade the server, then when powering it on I saw the debian install cd menu.
gparted showed a "unformatted drive" and I was able to recover the partition table with testdisk. then I had to reinstall grub with debian iso.
but this is the third time it happens; I have scheduled backups and restoring a backup I still don't have the partition table (so something is erasing it maybe?)

thanks

 

[fraksken]

I am afraid I am not sure about the root cause. It might have been me, but I am not sure.

Am I correct to understand you resolved the problem, and are now looking for the root cause?

p.s. I did not know about testdisk. That tool would have helped me a lot indeed.

 

[Enrico90]

problem is not resolved, because now I'm 90% sure the machine will not boot the next time I turn it off. Every time I have to restore the partition table and reinstall grub, but at least now the machine is running and working as expected (until the next shutdown)

 

[fraksken]

Seems like you have a different underlying problem then me. I managed several reboots of the server after restoring the problem.
I would immediately proceed to scan the system for rootkits. The partition table resides in the master boot record. if you systematically have problems there, something is affecting it.
It might be something else too though, but that would be my first guess.