Unraid vs TrueNAS vs OpenMediaVault: The Complete NAS OS Comparison

Updated: 2026-04-29

Last updated March 2026 · 10 min read

Choosing the right NAS operating system is just as important as choosing the right RAID configuration. The three most popular options for DIY NAS builds are Unraid, TrueNAS, and OpenMediaVault. Each has a fundamentally different philosophy.

Try it yourself! Compare RAID configurations with your drive sizes.

Open RAID Calculator →

Unraid – The Flexible All-Rounder

Unraid uses a unique parity-based storage system where each drive maintains its own filesystem. The largest drive serves as parity, allowing recovery if any single data drive fails. Drives spin up independently and you can read individual drives outside the array.

Storage: Custom parity system (1 or 2 parity drives). Mixed drive sizes work perfectly. Drives are individually readable – if parity AND a data drive fail, you only lose that one drive's data, not everything.

Docker & VMs: Excellent built-in Docker and VM support with a GPU passthrough. The Community Apps store makes installation trivial.

Cost: Paid license ($59 Basic / $89 Plus / $129 Pro, one-time). The license tier limits how many storage devices you can use.

Best for: Media servers, mixed-workload homelabs, users who want Docker + NAS in one box, people who upgrade drives incrementally.

TrueNAS – The Enterprise-Grade Option

TrueNAS (formerly FreeNAS) is built on ZFS, arguably the most advanced filesystem available. It provides checksumming, self-healing, snapshots, and replication out of the box.

Storage: ZFS with RAIDZ1/Z2/Z3 or mirrored vdevs. Once a vdev is created, you cannot add drives to it (you can only add new vdevs). This makes initial planning critical. ZFS uses all identical drives within a vdev.

Performance: Extremely fast, especially with enough RAM. ZFS uses RAM aggressively for caching (ARC), so 32GB+ is recommended for larger pools.

Cost: TrueNAS CORE and SCALE are free and open source. Enterprise support is available as TrueNAS Enterprise.

Best for: Data integrity purists, backup servers, users who want enterprise-grade features for free, environments where silent data corruption is unacceptable.

OpenMediaVault – The Lightweight Debian-Based Option

OMV is a Debian-based NAS solution that runs on almost anything, including Raspberry Pis. It uses traditional Linux RAID (mdadm) and standard filesystems like ext4 or Btrfs.

Storage: Standard Linux software RAID (RAID 0/1/5/6/10) via mdadm, plus SnapRAID for parity-based setups similar to Unraid (via plugin). MergerFS can pool drives of different sizes.

Resources: Extremely lightweight – runs on 1GB RAM. Perfect for repurposing old hardware or low-power builds.

Cost: Completely free and open source.

Best for: Budget builds, Raspberry Pi NAS, Linux enthusiasts, users who want full control over their Debian system.

Head-to-Head Comparison

Mixed drive sizes: Unraid handles this natively and elegantly. TrueNAS requires all drives in a vdev to match. OMV with SnapRAID+MergerFS supports mixed sizes but requires more setup.

Data integrity: TrueNAS (ZFS) wins decisively with copy-on-write and checksumming. Unraid and OMV rely on the underlying filesystem without end-to-end verification.

Ease of use: Unraid has the most polished web UI. TrueNAS SCALE has improved significantly. OMV is functional but can feel rough around the edges.

Docker/Apps: All three support Docker. Unraid's Community Apps make it easiest. TrueNAS SCALE has built-in app catalogs. OMV uses standard Docker Compose.

Expandability: Unraid lets you add one drive at a time. TrueNAS requires adding entire vdevs. OMV (with mdadm) allows adding drives to existing arrays with some effort.

Try it yourself! Compare RAID configurations with your drive sizes.

Open RAID Calculator →

HexOS – TrueNAS Made Simple

HexOS (launched 2024) is built on top of TrueNAS Scale with ZFS underneath. Same enterprise-grade data integrity, but with a plug-and-play UI designed for home users — no command line, automatic disk setup, simplified pool management. Free for home use. hexos.com.

My Recommendation

Pick Unraid if you want the most flexible, beginner-friendly experience with Docker support and don't mind paying once. Pick TrueNAS if data integrity is your top priority and you can commit to uniform drive sizes. Pick OMV if you want free, lightweight, and full Linux control.