NAS software protects and serves your files; a hypervisor like Proxmox runs everything else as isolated virtual machines and containers on the same box. Most homelabs eventually want both, and the fastest way there without buying two separate computers is running the NAS operating system as a VM on Proxmox with a disk controller passed straight through to it.
This is the strategic layer, not the product reviews: four detailed write-ups already live on this site, Proxmox VE, TrueNAS, Unraid, and OpenMediaVault, covering installation, licensing, and hardware specifics for each. This one is about the decision that comes before any of that: pure NAS, pure hypervisor, or one box doing both.
What’s actually different between a NAS and a hypervisor?
A NAS operating system exists to protect data and hand it out over the network. TrueNAS, Unraid, and OpenMediaVault each do this with a different storage engine underneath, ZFS, a parity array, mdadm software RAID, but the job is the same: turn a pile of drives into SMB and NFS shares that don’t quietly corrupt over the years. A hypervisor exists to run more than one operating system on one physical machine at the same time. Proxmox VE is the popular free option in the homelab world, splitting a box into virtual machines and lightweight LXC containers that stay out of each other’s way.
The line between the two has gotten blurry on purpose. TrueNAS and Unraid both run Docker apps and full VMs now, which makes them part-time hypervisors. Proxmox happily builds ZFS pools and shares them over NFS, which makes it a part-time NAS. Nothing on this shortlist does only one job anymore. What actually matters for your build isn’t which piece of software counts as “the NAS one,” it’s which piece gets to own the physical disks.
Dedicated NAS, dedicated hypervisor, or one box doing both?
Three architectures cover almost every homelab. Which one fits depends less on the software and more on how much you trust one motherboard with everything you own.
| Category | Dedicated NAS only | Dedicated hypervisor only | Combined (Proxmox + NAS VM) |
|---|---|---|---|
| What it’s for | File storage, backups, a media library that needs to survive a drive failure | Running several unrelated services and operating systems on one box | Both jobs, on one physical machine |
| Hardware | A case with several drive bays, a modest CPU | Any decent x86 box; RAM scales with how many VMs stack up | A beefier box: more RAM, an HBA in IT mode, an IOMMU-capable motherboard |
| Failure isolation | A dead hypervisor elsewhere never touches this box’s data | A dead NAS elsewhere never takes the hypervisor’s other VMs down with it | One motherboard failure can take out storage and every VM at once |
| Setup complexity | Low: install, build a pool, add shares | Low to medium: install, create VMs | Medium to high: IOMMU groups, HBA passthrough, VM-inside-hypervisor networking |
| Ongoing cost | One box, modest power draw | One box, power draw scales with VM count | One box total, cheapest overall if you only want one machine in the closet |
| Best fit | Anyone who wants storage to work and mostly be left alone | Anyone whose priority is services, storage is secondary | Anyone with one machine’s budget who’s fine troubleshooting passthrough once |
None of these is objectively correct. Two separate boxes, a NAS and a hypervisor talking to each other over the network, is the most forgiving setup to troubleshoot, because a kernel panic on the Proxmox side never touches a file sitting on the TrueNAS side. The combined build is the one most homelabs actually end up running anyway, mostly because buying, powering, and finding closet space for two machines is a bigger ask than learning PCI passthrough once.
How the Proxmox + TrueNAS all-in-one setup actually works
The pattern that shows up constantly in homelab builds is Proxmox VE on bare metal, with TrueNAS, Unraid, or OpenMediaVault installed inside a VM, and the physical SATA controller or HBA handed to that VM directly through IOMMU. TrueNAS then sees real disks instead of a virtual disk file sitting on Proxmox’s own storage, so ZFS can do the checksumming and self-healing it’s actually built for. Proxmox handles everything else on the same hardware: a Docker VM, Home Assistant, a Windows box for the one app that needs it.
What a working combined box looks like: Proxmox as the base, TrueNAS or Unraid in its own VM holding the physical disks, and everything else, Docker, Home Assistant, maybe a Windows VM, running alongside it. One login, one power cable, one machine in the closet instead of two.
A quick way to check whether a Linux box even has virtualization and IOMMU support before going further:
egrep '(vmx|svm)' /proc/cpuinfo
dmesg | grep -e DMAR -e IOMMUThe first line confirms the CPU can virtualize at all, VT-x on Intel, AMD-V on AMD. The second checks whether IOMMU is actually active at boot, which needs both a BIOS setting and a kernel boot flag, not just supported hardware. Proxmox’s own PCI(e) passthrough documentation covers the rest of the setup in detail once both checks come back clean.
Storage now depends on the hypervisor’s health. Handing a physical device to a VM depends on the motherboard exposing IOMMU cleanly, something consumer boards don’t always do, and an HBA sharing a group with the network card is a common surprise. Once the disks live inside a VM, a botched Proxmox update or a hung host can take the NAS down with it, which never happens when the two run on separate machines.
The hardware that actually matters for a combined build
Hardware: RAM is the first thing to get generous with. TrueNAS and OpenMediaVault both run comfortably starting around 16 GB, but that number climbs fast once VMs stack up on the same box, budget 32 GB as a realistic floor for anything doing both storage and a handful of services. ECC RAM is worth the small premium if the budget allows it: ZFS checksums data in RAM before writing it, so a memory error can in theory corrupt data before ZFS even notices. It’s not required and plenty of homelabs run fine without it, but for data you can’t just re-download, it’s cheap insurance. For the disk controller, the community default is an LSI HBA flashed to IT mode, never a hardware RAID card; ZFS and Unraid’s array both want to see raw disks directly, SMART data included, and a RAID controller hides that behind its own abstraction. Used LSI 9207-8i or 9300-8i cards are inexpensive secondhand and cover eight drives per card.
Before buying anything for a combined build: confirm the motherboard’s IOMMU support and group layout match what the build actually needs. It’s the one step that’s expensive to skip.
- Confirm VT-d/AMD-Vi is exposed in the BIOS on the exact motherboard, not just VT-x/AMD-V.
- Check how that board’s IOMMU groups split; an HBA sharing a group with the network card is a common surprise.
- Budget for an HBA in IT mode instead of reusing a RAID controller already sitting in a drawer.
- Size RAM for the heaviest workload the box will run at once, not the average one.
Proxmox vs TrueNAS: which one do you actually install first?
If the honest answer to “what does this box need to do” is mostly file storage, install TrueNAS, Unraid, or OpenMediaVault first, and add a VM or two later once something outgrows its built-in app support. If the honest answer is “a pile of unrelated services, plus maybe some storage,” start with Proxmox and add a NAS VM once passthrough is confirmed working. Trying to guess which one will feel more “correct” in the abstract usually wastes more time than just picking based on what the box needs to do on day one.
Our Proxmox VE and TrueNAS pages both cover this exact pairing from their own side: Proxmox’s page walks through the IOMMU and passthrough setup in more depth, TrueNAS’s page covers the ZFS and RAM side of the same build.
Where do Unraid and OpenMediaVault fit into this?
Unraid complicates the pure NAS-vs-hypervisor framing on purpose. Its parity array, Docker support, and KVM virtual machines all live in the same paid license, so a single Unraid box can be the whole combined setup without ever touching Proxmox, at the cost of a license fee TrueNAS and Proxmox don’t charge. It’s the closest thing on this shortlist to a genuine all-in-one, and worth a look before building the Proxmox-plus-VM version by hand. Our TrueNAS vs Unraid comparison covers that direct storage-only decision in more depth.
OpenMediaVault sits at the other end. It’s the lightest of the four, runs on a Raspberry Pi, and makes the most sense either as a small standalone NAS on modest hardware or as a lightweight VM inside a Proxmox box for anyone who doesn’t want ZFS’s RAM appetite or Unraid’s license fee for what’s ultimately a modest amount of data.
Mistakes worth avoiding
- Passing an entire HBA through to a VM without checking IOMMU groups first, then discovering it’s bundled with the network card.
- Storing the only copy of anything on a combined box with no separate backup, because “the hypervisor is right there too” isn’t a backup strategy.
- Undersizing RAM for the combined workload, then wondering why ZFS and three VMs are all fighting over the same 16 GB.
- Reusing an old hardware RAID controller instead of buying a cheap flashed HBA, then chasing phantom disk errors for a week.
FAQ
Can I run TrueNAS safely as a VM on Proxmox?
Yes, and it’s one of the most common homelab patterns there is, as long as the physical disk controller is passed through via IOMMU rather than presenting TrueNAS with virtual disks. The trade-off is that TrueNAS’s uptime now depends on the Proxmox host staying healthy, something a fully separate NAS avoids.
Do I need ECC RAM for a combined NAS and virtualization box?
No. TrueNAS and Unraid both run fine on non-ECC RAM, and most homelabs do exactly that. ECC lowers the already small risk of a memory error corrupting data before ZFS checksums it, which matters more the less replaceable your data is. Treat it as a nice-to-have added when the budget allows, not a requirement that blocks anyone from starting.
Is Unraid a good alternative to building Proxmox plus TrueNAS by hand?
For a lot of people, yes. Unraid bundles the array, Docker, and VMs into one license and one interface, skipping the IOMMU passthrough setup entirely. The trade-off is the license cost, and giving up ZFS’s checksumming unless a ZFS cache pool is added on top, which Unraid supports but doesn’t require.
What if my motherboard doesn’t support IOMMU or VT-d?
Then passthrough isn’t happening on that board, and the combined single-box approach isn’t really available without new hardware. A dedicated NAS on one machine and Proxmox, or just Docker, on another is the fallback, and it’s genuinely not a worse setup, just a different one with an extra box to power.
Should a beginner start with a NAS or with Proxmox?
Whichever problem actually exists right now. If storage is the pain point, photos scattered across drives, or a media library that’s outgrown one disk, start with a NAS and its OS of choice. If the pain point is wanting to run several unrelated services without them stepping on each other, start with Proxmox. Our homelab setup guide for beginners covers the decision at an even earlier stage, before either of these is on the table.
Once the architecture is picked, the four individual pages on this site cover the parts that actually change from machine to machine: Proxmox VE for the hypervisor side, TrueNAS for a ZFS-based NAS, Unraid for the paid all-in-one array-plus-VMs option, and OpenMediaVault for the lightest, Raspberry Pi-friendly NAS. Portainer is worth adding once Docker is running inside any of these, for a dashboard instead of SSH sessions to manage containers. Our NAS & Storage category collects the rest of what we publish on this side of the homelab, and the homelab setup guide for beginners is the right starting point if none of this is settled yet.