UPDATE🔗

I had to learn it the hard way... Just don't do what I did and get yourself an HBA controller right away!

Otherwise you will run into (performance) problems sooner or later.

I was in the situation to install Proxmox on a second hand HP DL380 Gen8 Server with a P420i RAID controller.

Since Proxmox supports installation to ZFS out of the box I wanted to make use of that. Unfortunately with the somewhat older hardware there were a few hiccups I ran into. Hopefully with this blog entry I can help some people to save time and get their system up and running a bit faster than I did.

Ideally get a real HBA card and use that. If that is not possbile the following steps should work.

TL;DR🔗

• define each disk as RAID 0 volume
• set the first and second as primary and secondary boot volume in the graphical SSA (F5? during boot)
• install Proxmox on a mirrored ZPOOL using the first two disks

The long version with some background🔗

Ideally the internal P420i RAID Controller would have a full HBA mode to get direct access to the disks and install Proxmox with a ZFS Mirror / RaidZ config of our choice.

Unfortunately in HBA mode the P420i does not allow us to boot from any of those drives. Due to the lack of any other bootable drives I resorted to configuring each drive as a RAID 0. Now I tried installing Proxmox on a RaidZ2 with 6 drives but had to realize in dismay that it would not boot.

At some point I noticed that GRUB did not see all 6 drives, or at least 4 to assemble the ZFS pool to start the system. Turns out that during the bootloader stage the controller somehow only shows the logical drives that are defined as boot volumes.

I came to terms that I had to reconsider my pool's VDEV layout. Use a dedicated pool for the system and have the bigger pool for the storage separate. This meant selecting the first and second logical volume / RAID 0 drives as primary and secondary boot volume in the graphical Smart Storage Administrator. You should be able to enter it by hitting F5 at the right point in the boot process.

With this the first two drives should be visible for GRUB. During the Proxmox installation I only chose the first two drive in a mirrored configuration and at the next boot, lo and behold, it booted as expected!

After that creating a new ZPOOL with the rest of the disks can be done quite easily via the Proxmox GUI or the CLI.