Xpenology on Proxmox VE 8.2.4 with HDD passthrough

Requirements

• Proxmox VE 8.2.4+
• CPU with VT-d support (IOMMU)
• Drive(s) you want to pass through

Download the bootloader image

The most popular bootloader right now is Arc (community-maintained). Download the latest release from:

https://github.com/AuxXxilium/arc/releases

Download the .img.zip file for the model you want to emulate (DS923+, DS1522+, etc.).

# Upload to Proxmox and extract
unzip arc-*.img.zip

Create the VM on Proxmox

Step 1: Upload the image to Proxmox

scp arc.img root@proxmox:/var/lib/vz/images/

Step 2: Create the VM

Create a VM with these settings:

• OS: Do not use any media
• System: q35, OVMF (UEFI), add EFI disk
• CPU: host type (to pass through CPU flags)
• Memory: 4 GB+
• Network: VirtIO

Important detail: arc.img here is a prebuilt Arc bootloader image, not the DSM installer itself. The qm importdisk command only imports that image into local-lvm so Proxmox can expose it as a disk that you later attach to the VM.

# Import the existing arc.img file into VM 100 storage as a disk
qm importdisk 100 /var/lib/vz/images/arc.img local-lvm

In practical terms, this step is:

1. Upload arc.img to the Proxmox host
2. Import arc.img as an unused disk for the VM
3. Attach that disk to the VM over SATA
4. Boot the VM from that bootloader disk

DSM installation only happens later, after you open the Arc UI and build the DSM boot target for the Synology model you want to emulate.

Step 3: Attach the disk

In the Hardware tab, select the unused disk → Edit → set bus to SATA, not VirtIO.

HDD passthrough

Enable IOMMU

Edit /etc/default/grub:

GRUB_CMDLINE_LINUX_DEFAULT="quiet intel_iommu=on iommu=pt"

update-grub
reboot

Find the disk ID

ls -la /dev/disk/by-id/ | grep -v part

Pass the disk through to the VM

# Add /dev/sdb to VM 100
qm set 100 -sata1 /dev/disk/by-id/ata-WDC_WD40EFRX-XXXXXXXX

Installing DSM

1. Boot the VM, open the Arc bootloader UI at http://<vm-ip>:7681
2. Choose a model (DS923+), select DSM 7.2.1
3. Build & Boot
4. Open http://<vm-ip>:5000 to complete the DSM installation

Reading SMART data via passthrough

Because the HDD is passed through directly, DSM can read SMART data natively:

Storage Manager → HDD/SSD → select the drive → Health Info

You will see full SMART attributes exactly as you would on a bare-metal server.