[SOLVED] After Update -> Grub rescue console

[Yakuraku]

Hey folks,

I installed Proxmox today (downloaded yesterday).
It was success full installed (ZFS) and created some vms. Everything was fine and reboot was all ok.

Then I performed an update (without any errors). After this reboot, the system does no longer boot. To be precise, the server boots into grub rescue. The only additional information provided is:
"error: [2] incorrect dnode type: 16!=21"

Anybody has an idea, how this problem is created?

 

[sigxcpu]

The dataset seems to be corrupted. Try to repair it booting from a rescue system with ZFS support.

 

[fireon]

This should help you: https://forum.proxmox.com/threads/can-not-boot-to-os-after-upgrade-proxmox-4.29419/

 

[Yakuraku]

I have tried to reinstall the Proxmox to fix the problem, and after another update/upgrade, I got the same problem again ("error: [2] incorrect dnode type: 0!=21"). My ZFS root pool is a 3-mirror setup. Souldn't it be save against a corrupted dataset? Could that be a known bug I haven't found?

@sigxcpu & @fireon: Thanks for your replies. I'll try to chroot and fit it with a proxmox 3.4 / 4.0 cd (I can't use 4.2 because of this https://forum.proxmox.com/threads/debug-mode-no-inputs-possible.26117/ )

 

[Yakuraku]

Just started with the proxmox 3.4 and checkt the zpool, which was ok (no corruption)
I chrooted to the rpool but now I can not perform grub-install /dev/sda (grub-install error cannot find a device for /boot/grub (is /dev mounted?) Did i miss to give the /dev to chroot?

 

[Yakuraku]

Recovered my system.
Used this guide to chroot into the installed system: https://pve.proxmox.com/wiki/Recover_From_Grub_Failure
performed an update-grub2
On reboot I select the older kernel (the newest has an error message with "lz4 compression, load kernel first")
The system is now available again.

 

[fireon]

The system is now available again.

I am pleased