TrueNAS Core Vs Scale - Grub issue

TrueNAS General
1

I was using Core for a bunch of time now without real issue on my HP DL380 G5.
I upgraded all my other machines without real issues except this server.

Symptoms:
I install a fresh Scale on 2 USB external mechanical hard drives, installation goes smoothly (BIOS only, not UEFI), I reboot, I set the truenas_admin password, log in and everything seems OK. As far as I restart the machine, GRUB reports an error (ex: unknown filesystem) and stays in rescue mode

Tests:

  • tried to install from version 24.04 to 25.10.1, the grub error can change (attempt to read outside disk, “grub grub grub”, unknown filesystem, and maybe some other one I do not remember)
  • tried to install on a single disk
  • tried to boot systemrescue+zfs, the boot disks seems ok (as far as I can tell)
  • tried to scrub the boot-pool after the first successful boot and reinstall grub on both hard drives
  • tried to change the 2 hard drives and tries to change the USB/SATA adapters
  • tried installation from DVD, from USB stick created with rufus (latest version did not asked me DD mode), from a Ventoy different USB stick which loads the ISO
  • tried to reboot without changing anything and tried to reboot after reloading backup configuration

As far as I saw, the boot loader is different from Core and Scale which can explain why only Scale has the issue.
What is really surprising is that the first boot succeed, then, I cannot boot anymore without reinstalling.

Note: I might be slow to answer because I will have a very limited access to the server for the next 2 weeks.

Any advice is welcome. Thanks

2

Please strictly follow the official recommended upgrade path.

3

I forgot one of the tries:

  • I upgrade using the web interface from latest 13 version
4

I attempt the installation of beta 26 on 2 external USB2 3”1/2 disks with external power and the first boot displayed the attempt to read outside disks error.

I retried the installation using uefi, the error remain, I am pretty sure the server is not uefi compliant.

So I tried to install again in BIOS mode to work on the error and… no more error ???

I will see how the upgrade to final 26 release will go but I really wonder if there is an issue during the grub installation in m’y specific case… maybe too specific to be managed.

And as it is now working, I have no intention to try again my luck. Maybe later during the upgrade?

5

I have updated from 26 beta 1 to 26 beta 2 directly from the UI and:

Welcome to GRUB!

error: no such device: 66…bf.
error: unknown filesystem.
grub rescue> _

I have not tried a boot disk reinstallation as previouly done.

There is definitely something strange with the new boot process since Core version on that specific device (I have other computers with no issue at all) but I cannot figure out what by myself.

Any suggestion is welcome, and if it can improve the setup, I would be please to have contribute somehow