ZFS & proxmox-boot-tool

moeffju

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Apr 22, 2019
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I installed Proxmox 7.x through the ISO on a Hetzner test server on ZFS with 4 HDDs. When upgrading to Proxmox 8, I encountered the documentation on switching to proxmox-boot-tool again (https://pve.proxmox.com/wiki/ZFS:_Switch_Legacy-Boot_to_Proxmox_Boot_Tool) but I'm not sure if I'm understanding it correctly or if I need it.

The current system is booted in legacy boot mode, and it appears to work fine. Unfortunately I did not note the version of grub installed before upgrading, so now it's the version contained in Proxmox 8. The guide to switching to proxmox-boot-tool implies that there should be a separate partition of 512M usable to convert to UEFI boot, but my partition structure looks different and I don't recall changing anything on purpose:

Device Start End Sectors Size Type
/dev/sdd1 48 2047 2000 1000K BIOS boot
/dev/sdd2 2048 4196351 4194304 2G Solaris /usr & Apple ZFS
/dev/sdd3 4196352 31251759070 31247562719 14.6T Solaris /usr & Apple ZFS

part2 on each disk is added into a 'bpool' zpool, and part3 is used for the ZFS rpool. Disks are using GPT disk labels.
To me, it looks like part1 is not used/needed at all, part2 is way oversized for /boot, and there is no "placeholder" partition for UEFI boot.

As this is more of a home lab server, I did not document my installation settings as diligently as I would have for production systems, so I'm hoping somebody can help me understand:

- Where does this part1 "BIOS boot" partition come from? How do I figure out if I actually need that?
- Did I misconfigure something in Proxmox / ZFS and should part1 be the ZFS bpool and part2 the potential UEFI placeholder partition?
- If the system boots and runs fine, does it even make sense to migrate to using proxmox-boot-tool?
- If yes, what would I need to look out for? I assume I would have to resize the bpool partitions and create a new UEFI partition on each disk?

Thanks in advance for any help - I am a bit stumped how to dig further here and don't want to risk making the server unbootable.
 
I would keep that just in case you need to boot via legacy boot.
Partition table needs to be GPT format for UEFI to work.
Older Hetzner servers dont support UEFI booting out of the box, so be aware of that, the good news is if you on such a server you can request to switch to UEFI mode on a support ticket, they will need to do a reboot and very short downtime to make this change.
If the system ends up not booting you can either test (and change if needed) it in qemu from rescue OS or request a temporary KVM from Hetzner. If using rescue OS I would boot proxmox iso in qemu with matching version of installation so to ensure you have right version of ZFS.
 

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