Proxmox VM suddently not booting with error “attempt to read or write outside of disk ‘hd0′”

This afternoon an important server suddenly stopped booting. Below if a screenshot of the final output, but earlier on the Proxmox boot sequence was this other telling error:

attempt to read or write outside of disk 'hd0'


It’s an Ubuntu 22.04 server and I run an extremely stable environment so needless to say I kind of went into a panic.

The point is a disk crash or hard drive that doesn’t start up is never much fun.

I also just do apt dist-upgrade and although I’ve done that for years, the inherent upgrades of core OS files is always something to ponder.

Fortunately the error was really easy to google and fortunately Proxmox is a world-class product.

I quickly found something on the Proxmox forums with a fresh date (about a month old) so I knew I was on the right track.

Herein Fabian, a legend on the forums and staff member of Proxmox, clearly explains the problem namely:

> this is usually the result of
> – big disks or hardware raid (the latter might just “lie” about the disk size)
> – in combination with legacy bios

There are a few remedies mentioned and luckily the very first one worked for me:

> – switch to UEFI which handles modern disk sizes…

Alora! Problem solved. Nervous moments I tell you.

Upon closer inspection I could see what apt dist-upgrade did. I’m not exactly sure which specific file broken the UEFI sequence, but some of these files that were installed could well be the culprits:

Preparing to unpack .../08-grub-efi-amd64-bin_2.04-1ubuntu47.4_amd64.deb ...
Preparing to unpack .../09-snapd_2.57.5+20.04_amd64.deb ...
Preparing to unpack .../11-cloud-init_22.3.4-0ubuntu1~20.04.1_all.deb ...


Share this article

Leave a Reply

Your email address will not be published. Required fields are marked *

Scroll to Top