TrueNAS Scale and Legacy BIOS

[doolbneerg]

I have an HP Microserver Gen 8 that I want to try out TrueNAS SCALE on, however this only supports the legacy BIOS/MBR boot.

I have gone through and got the installation process running. I have been able to install to the drive, but then can’t boot it. I know that there is an issue with HP Microserver Gen 8 with which drives it can boot off of when fully populated, but right now I am attempting to get it to only work with a single drive as that shouldn’t have any of the limitations.

When I look at the drive after the install looks like this:

Code:

Disk /dev/sda: 223.57 GiB, 240057409536 bytes, 468862128 sectors
Disk model: INTEL SSDSC2CW24
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 0D6ECE75-358D-4386-88B1-806BD3DC1FE8

Device Start End Sectors Size Type
/dev/sda1 4096 6143 2048 1M BIOS boot
/dev/sda2 6144 1054719 1048576 512M EFI System
/dev/sda3 34609152 468862094 434252943 207.1G Solaris /usr & Apple ZFS
/dev/sda4 1054720 34609151 33554432 16G Linux swap

I thought I saw stuff that indicated that the TrueNAS SCALE installer was supposed to install BIOS and EFI binaries, but when I look through the disk it looks like I am only seeing EFI binaries. Where should the legacy binaries be? Has anyone been able to use a GPT disk and boot to MBR. I am not sure if this is a Gen 8 server issue, or if you can never BIOS boot to a GPT disk. If possible, I would prefer to not have to do the USB boot trick.

Then I started down the path of setting up a USB boot chain loader setup. I created the drive and installed GRUB from an Ubuntu 22.04 LiveCD and I can boot into the boot menu. But, in GRUB it can’t see my primary drive. I tried loading part_gpt and zfs but I am not seeing the drive. Any ideas on how to debug this?

Lastly, the best I could find for the GRUB configuration for SCALE was https://www.truenas.com/community/threads/truenas-scale-grub-usb.95102/. However, that seems rather hard coded to a specific beta kernel. How do I figure out what path/kernel got installed with my install? Is there a way to keep it up to date or will I need to edit every upgrade?

 

[doolbneerg]

After doing a bunch of testing and debugging and installing Ubuntu like a dozen times... Apparently I that I hadn't switched the onboard controller back to AHCI. Now that I have it set to AHCI, I was able to install TrueNAS without any issues and it is booting to the GPT formatted drive. So if you are looking at this trying to find a solution for yourself, double or triple check that you are set to AHCI.

Also after doing that I was able to load the gpt and zfs mods in GRUB I was able to see the drive and the ZFS partitions. But since I can natively boot to my primary drive, I am not going to dig any deeper into the chain loading from the USB boot drive.