Installing FreeBSD: Auto (ZFS) + MBR (BIOS) = "Missing operating system"

V

Vurefozu

Hello.
Trying to install FreeBSD 13.1-Release (FreeBSD-13.1-RELEASE-amd64-disc1.iso) with configuration:
Partitioning: Auto (ZFS)
Partition Scheme: MBR (BIOS)
Pool Type/Disks: stripe: 1 disk

And I found that after the first reboot the system does not boot and a message is displayed: "Missing operating system"

Tested 3 times:
- on PC
- on the XEN virtual machine
- on QEMU virtual machine

In all three cases, the problem is reproduced.
Why is this happening? Is this a bug with the freebsd installer or is there something else I need to do?
Thank you.

freebsd-1.png

freebsd-2.png
 
Why use MBR in the first place? On systems younger than about 10 years you can safely use GPT, even if you're still on the traditional BIOS boot. I would recommend using GPT (UEFI+BIOS) on modern systems, even if your current system isn't capable of UEFI booting.
 
SirDice said:
Why use MBR in the first place?
Click to expand...
Just an old habit.

I have now switched to GPT. But I would like to understand why freebsd is not loaded from the installer.

If these are installer errors, then I will know this and suggest removing this item from the installer so that other users do not stumble upon this problem.
 
Vurefozu said:
But I would like to understand why freebsd is not loaded from the installer.
Click to expand...
MBR should work. "Missing operating system" usually indicates it's a BIOS issue, not booting from the correct disk for example.
 
"Missing operating system" message is usually contained in the standard mbr code and displayed more often than not when you dont have an active partition or the bootcode of the active partition is missing the 0x55 0xAA signature
(or something)
 
I'm wondering if there's still enough space for the ZFS bootcode in the slice/partition with MBR. It seems to have grown a lot the last few years.
 
the problem/thing is that is not even a partition; you just dd the code in a specific place inside the actual fs space
from the wiki above
zpool create zroot /dev/ad0s3
dd if=/mnt2/boot/zfsboot of=/dev/ad0s3 skip=1 seek=1024
 
covacat said:
the problem/thing is that is not even a partition; you just dd the code in a specific place inside the actual fs space
Click to expand...
Sure, but that space still needs to be large enough and not get overwritten by the filesystem you're putting on it.
 
SirDice said:
Sure, but that space still needs to be large enough and not get overwritten by the filesystem you're putting on it.
Click to expand...
yeah, its worse than a partition, you don't know how big the internal reservation is and what you may fsck up if you update the bootcode
 
covacat said:
you can probably still boot it by using this guide https://wiki.freebsd.org/RootOnZFS/ZFSBootSlice
Click to expand...
Thank you. This method is working. Installed from scratch manually, booted.

covacat said:
MBR + ZFS on root should be removed from the installer (in my opinion)
Click to expand...
Because According to the instructions https://wiki.freebsd.org/RootOnZFS/ZFSBootSlice, I managed to install it manually on ZFS + MBR (BIOS), which means that the freebsd installer does not install something correctly.
 
Vurefozu said:
Hello.
Trying to install FreeBSD 13.1-Release (FreeBSD-13.1-RELEASE-amd64-disc1.iso) with configuration:
Partitioning: Auto (ZFS)
Partition Scheme: MBR (BIOS)
Pool Type/Disks: stripe: 1 disk

And I found that after the first reboot the system does not boot and a message is displayed: "Missing operating system"

Tested 3 times:
- on PC
- on the XEN virtual machine
- on QEMU virtual machine

In all three cases, the problem is reproduced.
Why is this happening? Is this a bug with the freebsd installer or is there something else I need to do?
Thank you.

View attachment 15089

View attachment 15088
Click to expand...
Try other thing.

Install FreeBSD with Auto (ZFS) with GPT scheme and then still boot in BIOS mode. That works.

I tried several times with ZFS on MBR but was never able to boot from it.
 
Some time ago I tried a "whole disk ZFS" option. That is a pool that uses a whole unpartitioned disk. Later I noticed that it DID use MBR. But in that particular case, GRUB2 for MBR worked perfectly well. Later I abandoned that setup as it didn't show any advantage over partitioned approach...
 
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