Help With a Proxmox Setup - IOMMU Passthrough Questions

So I recently built a new Proxmox server on a Ryzen 5 1600 on an Asus Strix Gaming X470 to consolidate my pfSense, FreeNAS (Which ran some VMs for PiHole and Home Assistant), and Plex into one system.

I have a couple of questions:

  1. I’ve basically come to the conclusion that using Proxmox for ZFS is good enough and I don’t have to worry about doing a FreeNAS VM, should I even worry about getting an HBA card for 3 hard drives for it?

  2. If I go the route of the HBA card, Because I pass in a dual gigabit NIC for pfSense, It seems that I have only one slot left for splitting IOMMU groups. For my Plex setup I have the WinTV Quad tuner for my OTA Channels that goes into an x1 slot, my findings so far is that it’s grouped with other things such as the USB and SATA controller. As far as I’m aware there isn’t a way to break this group any further so that I can pass this tuner card into a VM correct?

Thanks in advance!

If you only have a few drives then I wouldn’t worry about the HBA. Onboard SATA may not be as fast as HBA SATA, but should be good enough, and I expect if you really want fast you have NVME. HDDs are not that fast anyway.

PCI pass thru isn’t something I have much of an idea about, but seems like what you are saying makes sense, and would seem to be a limiting situation unless you can get a BIOS upgrade to allow better segmentation of IOMMU groups, or you might need to find a different motherboard.

You might also want to update the thread subject to get more interest in IOMMU groups vs PCI passthru, as proxmox is probably even more niche.

It’s funny how after you post your question you find your answer after. Guess my Google-Fu about the HBA cards weren’t all there leading up to posting. But good to know that it’s still the case today!

Will take your advice and edit the Subject and hope for more answers on the IOMMU.

(Though, I will say that in my testing of plugging the drives into the onboard SATA instead of an HBA card, and using the tuner card in the other X16 slot that’s tied to the CPU, I was able to pass the tuner card through by itself to a VM.)