Trouble setting up Supermicro X9 with software RAID

[nwt]

I've tried setting up OPNsense once before on top of ESXi and almost got it completely working but put the project on the back burner. I've recently decided to give it another go, but this time with dedicated hardware. I'm using this Supermicro X9DBU-3F system with an Intel C606 chipset, plus two SSDs I want to mirror.

I'm not very experienced with software RAID, but I found these instructions for setting up GEOM.

I'm pretty sure this is about where I went wrong, so before I get too deep into posting screenshots of console output... Is GEOM meant to interact with a software RAID controller, or does it prefer simpler access to normal disks? I ended up installing to a volume generated by the controller, so maybe that's where I went wrong.

[nwt]

I've decided to go ahead and revert my disks to non-raid in the controller and now I see mirror/OPNsense in the drive list as shown in the GEOM instructions. However, when trying to install there, it fails immediately with code gpart 126.





Selecting ada0 results in the same error.

Earlier, when I had attempted to install to the controller raid1 volume, it seemed to install but then wouldn't boot afterward, showing some storage problems in the console output.





Here's what my onboard raid setup looks like. This was from before I reverted the disk status to non-raid.



edit: After disabling raid mode in the motherboard bios, it seems to be installing...

edit: Aaaaand it seems to boot up just fine