TrueNAS vs OpenMediaVault: Which NAS OS to Self-Host

TrueNAS vs OpenMediaVault: the short version

Both are free, open source operating systems that turn a spare PC into a network storage box. The difference comes down to one filesystem: ZFS.

TrueNAS is built around ZFS. You get snapshots, scrubs that catch silent data corruption, and RAID-Z redundancy, but ZFS wants real RAM (8 GB minimum, more if you run VMs or deduplication) and prefers whole disks it fully controls. OpenMediaVault is built around standard Linux filesystems like ext4, Btrfs, and XFS, so it runs comfortably on far less hardware and installs on a Raspberry Pi or old laptop.

Full feature comparison

Neither iXsystems nor the OpenMediaVault project publishes an official head-to-head comparison page. The table below is a neutral, third-party summary sourced to official documentation. Unraid is included as a third reference point because it is a live competitor in this search space and the right answer for some builds.

Sources: TrueNAS hardware guide (truenas.com/docs/scale/25.04/gettingstarted/scalehardwareguide/); OMV prerequisites (docs.openmediavault.org/en/8.x/prerequisites.html); Unraid buy page (account.unraid.net/buy).

Hardware requirements in detail

Sources: TrueNAS hardware guide; OMV prerequisites docs.

RAID and pool types compared

This is the single biggest decision-driver between the two and the area most comparison articles gloss over.

TrueNAS uses the ZFS vdev model. You build a pool from one or more vdevs, and each vdev has its own redundancy type:

• RAID-Z1: equivalent to RAID-5, tolerates 1 drive failure per vdev.
• RAID-Z2: equivalent to RAID-6, tolerates 2 drive failures per vdev.
• RAID-Z3: tolerates 3 drive failures per vdev. Rare in home labs.
• dRAID: a distributed RAID layout for large numbers of drives, rebuilds faster than RAID-Z.
• Mirror: two or more drives as a mirrored pair, best IOPS, lowest capacity efficiency.
• Stripe (no redundancy): for scratch pools only.

Drives in a vdev should be the same size. ZFS treats every drive as big as the smallest one, so a mismatched drive wastes the difference, same as traditional RAID.

OpenMediaVault's RAID is software RAID via mdadm. Supported modes: RAID 0 (striping, no redundancy), RAID 1 (mirroring), RAID 5 (single parity, similar capacity math to RAID-Z1), and RAID 10 (mirrored pairs). This runs on top of whatever filesystem you pick (ext4, Btrfs, XFS). OMV 7 and 8 use a plugin for software RAID configuration; it is not wired into the UI by default the same way ZFS is on TrueNAS.

Unraid uses a parity-array model, not traditional RAID. One or two parity drives protect the entire array; data drives can be any size and mix of brands. This is Unraid's headline differentiator: add a 4 TB drive to a shelf of 8 TB drives and it just works, without re-striping the array. The tradeoff is that Unraid reads one drive at a time, so it cannot stripe reads across drives the way a RAID-Z or mirror vdev can.

Data integrity: why ZFS matters

ZFS checksums every block of data it writes. Run a scrub and it can detect silent corruption (bit rot) that a standard filesystem like ext4 has no way to catch. Combine that with RAID-Z redundancy and ZFS can repair the corrupted block automatically from parity data.

If your NAS holds anything you would be upset to lose (family photos, backups, irreplaceable files), that protection is worth the extra RAM. If your NAS is mostly a media library you could re-rip from the source, the risk-to-cost tradeoff shifts the other way.

Btrfs, available natively on OMV without any plugin, also checksums data and supports snapshots, which gives OMV users a credible middle-ground option: better data integrity than plain ext4, without the RAM floor of ZFS.

Can you expand storage later?

This used to be the classic argument against ZFS. It is less true now, but the three still grow differently.

TrueNAS / ZFS: Since TrueNAS 24.10 Electric Eel (built on OpenZFS 2.3), you can extend an existing RAID-Z vdev one drive at a time. The catch: data already on the pool keeps its old data-to-parity ratio until it is rewritten, so the reported free space grows by less than a full drive at first. The other route is adding a whole new vdev (another set of matched drives), which is still the cleanest way to grow a large pool.

OpenMediaVault / mdadm: mdadm RAID-5 and RAID-6 arrays support adding a drive and reshaping the array. It is slower than a fresh build but it works without losing data.

Unraid: Adding a drive to the array requires one parity check (a few hours on large arrays) but no data migration. This is the easiest single-drive expansion model of the three.

If your plan is to start small and add one drive per year, all three can do it now. Unraid is the least fussy (any size, any brand), TrueNAS works if you keep buying the same drive size.

ARM and Raspberry Pi support

OMV runs on ARMv7 and ARMv8 boards, including Raspberry Pi 3 and Pi 4 class hardware, with a 1 GB RAM minimum. This makes it the only option in this comparison for readers repurposing a Pi or an ARM SBC.

TrueNAS and Unraid both require x86_64 hardware. If your only spare machine is a Raspberry Pi, OMV is the answer by default.

Ease of use and app support

Both have a clean web UI. OpenMediaVault's interface is simpler and faster to learn if file sharing is all you want (SMB, NFS, FTP shares, basic user permissions). The plugin catalog covers Docker, extra filesystems, and backup tools, but it is maintained by community volunteers and smaller than TrueNAS's catalog.

TrueNAS Community Edition's UI has more depth because it does more: the built-in Docker app catalog lets you run Immich, Jellyfin, Nextcloud, or Pi-hole directly on the NAS itself without a separate Proxmox or Docker host. (TrueNAS dropped its old Kubernetes app backend for plain Docker in 24.10 Electric Eel, which made custom apps far simpler.)

Unraid's Community Applications plugin serves a similar Docker-catalog role, with a large selection of pre-configured containers and a strong home-server community around it. Of the three, Unraid arguably has the most active hobbyist community for Docker-on-NAS workflows, but it is the only one that charges a license fee.

What about Unraid?

Unraid is a paid NAS OS, not a free alternative to TrueNAS or OMV. Pricing (one-time, as of the 2026 buy page):

• Starter: $49, up to 6 storage devices, includes 1 year of updates, perpetual license to run that version after the updates window.
• Unleashed: $109, unlimited storage devices, 1 year of included updates.
• Lifetime: $249, unlimited devices, lifetime updates.

Upgrade paths exist (Starter to Lifetime is $209; Unleashed to Lifetime is $149). Legacy keys purchased before March 27, 2024 keep lifetime updates under the old pricing. This is a one-time purchase model, not a subscription.

Unraid's core differentiators are mismatched drive tolerance (any size, any brand, add one drive at a time), built-in Docker and KVM VM support without plugins, and a large community of home-server hobbyists. The tradeoff is cost and the fact that Unraid is not open source.

Which one should you pick

Pick TrueNAS Community Edition (25.10 Goldeye) if: you have 3 or more matched drives, at least 8 GB RAM and a 16 GB SSD to boot from, and data integrity is the top priority. The built-in Docker app catalog and ZFS snapshots make it a strong all-in-one for a dedicated NAS server. x86_64 only.

Pick OpenMediaVault 8 Synchrony if: you are repurposing old hardware, a laptop, or a Raspberry Pi with as little as 1 GB RAM. OMV's Btrfs and ext4 support keep data loss risk reasonable without the ZFS RAM overhead. Best for readers who want one or two drives and simple file shares.

Pick Unraid if: mismatched drive sizes are non-negotiable, you want Docker and VMs out of the box like TrueNAS but with a more flexible storage model, and you are comfortable paying a one-time license fee. Not the right choice if your budget is zero.

Neither, use something else if: you just want one or two self-hosted apps and do not need dedicated NAS-grade storage management. A Proxmox VE box running plain Docker containers may fit better; see our home lab app roundup for the shortlist. Once storage is sorted, self-hosting n8n is a good first automation app to run on it.