PCI Passthrough


New Member
Aug 12, 2023
Hello Everyone,

Quiet a newbie still, but I run into issues with passing through my sata drive to a vm running Openmediavault as my nas. Reason for me doing this is, that I can't get my disks to spin down if i have proxmox managing them. Since I will mainly use my nas on weeknds not necessary to keep them spinning 24/7.

Anyways I set it all up how it's explained on various sources: Iommu enabled, checked if everything is working and then passed through the controller to the vm via GUI all works fine. Then I setup the drives in Openmediavault, again no problem. But when I started to copy files to it the ram usage increases till 95% then the file transfer speed drops to 0.0mbit/s and after a while it interrupts completely saying it cant copy the file.
When I acess the vm's console I get a bunch of errors looking like this:

Since I saw these kind of messages when i was setting up the IOMMU:
DMAR: IOMMU feature fl1gp_support inconsistent
DMAR: IOMMU feature pgsel_inv inconsistent
DMAR: IOMMU feature nwfs inconsistent
DMAR: IOMMU feature eafs inconsistent
DMAR: IOMMU feature prs inconsistent
DMAR: IOMMU feature nest inconsistent
DMAR: IOMMU feature mts inconsistent
DMAR: IOMMU feature sc_support inconsistent
DMAR: IOMMU feature dev_iotlb_support inconsisten

I checked and found a thread where people complained about not working pci passthroughs having the same motherboard and cpu like i do: j4125 intel celeron. I tried again using an older kernel as was recommended in that thread (https://forum.proxmox.com/threads/p...nel-5-13-19-1-upgrade-from-7-0-to-7-1.100961/). But having the same error.

Additionally I realized that it sometimes is extremely time consuming to shutdown the vm via proxmox. I don't know but it seemed to be only since I passed through the controller. so maybe it is linked but I have no idea.
Does anyone have a clue on how to solve this?


The Proxmox community has been around for many years and offers help and support for Proxmox VE, Proxmox Backup Server, and Proxmox Mail Gateway.
We think our community is one of the best thanks to people like you!

Get your subscription!

The Proxmox team works very hard to make sure you are running the best software and getting stable updates and security enhancements, as well as quick enterprise support. Tens of thousands of happy customers have a Proxmox subscription. Get yours easily in our online shop.

Buy now!