TrueNAS vs Unraid: Which NAS OS Wins?

You've got a 4 TB drive, an 8 TB drive, and a 14 TB drive you pulled from an old machine, and you want to turn them into one home NAS for media, photos, and backups. Before you install anything, you have to pick the operating system — and that single choice decides whether those mismatched drives cooperate or whether you waste half their capacity. Get it wrong and you're rebuilding the whole array next month.

In my homelab I run ZFS-backed storage, so I've felt both sides of this: the safety of ZFS and the frustration of its old rigidity around disk sizes. Here's how the decision actually breaks down.

You've got a pile of mismatched drives and one decision to make

Both systems turn a box of disks into shared storage with parity protection, apps, and containers. The difference is in their core philosophy — and that philosophy is exactly what determines how well your specific drives fit.

Two different philosophies of storage

TrueNAS SCALE is ZFS-first. ZFS brings checksums on every block, snapshots, and self-healing — the kind of integrity that catches silent data corruption before it spreads. It's open-source and completely free.

Unraid is built around a flexible parity array designed for approachable home use. Its headline trick is letting unlike-sized disks live in the same array without wasting space, and it's widely considered the easiest NAS OS to learn. It's a paid, one-time license.

The tension in one line: data-integrity-and-free versus flexibility-and-ease.

The drive question: ZFS pools vs the Unraid array

This is the heart of it. Historically, ZFS wanted same-size disks grouped into a vdev, and growing capacity meant adding a whole new vdev — awkward for a home budget. That changed: OpenZFS 2.3 introduced RAIDZ expansion, now in TrueNAS SCALE, so you can add a single disk to an existing RAIDZ pool.

Unraid's array was built for this from day one. A 4 TB, an 8 TB, and a 14 TB drive coexist without waste; you expand one disk at a time, and only your parity drive must be as large as your biggest data drive. And since Unraid 7 added native ZFS pools, you can even run a real ZFS pool on Unraid if integrity matters more than mixing sizes.

Cost: free vs a license (and what the license really buys)

TrueNAS SCALE is $0, with every feature unlocked.

Unraid is a one-time purchase, in three tiers (from unraid.net): Starter $49 (up to 6 storage devices), Unleashed $109 (unlimited devices), and Lifetime $249 (unlimited devices). All three are perpetual licenses — the software keeps running forever. The catch is updates: Starter and Unleashed include one year of software updates, while Lifetime includes them indefinitely. When updates lapse, you don't lose your NAS; you simply stop getting new releases until you extend.

The decision table: TrueNAS vs Unraid head-to-head

Here's the comparison as I weigh it in practice:

Dimension	TrueNAS SCALE	Unraid
Cost	Free	$49–$249 one-time
Disk flexibility	Best with same-size disks	Mix any sizes freely
Data integrity	ZFS checksums + self-healing	Parity array, or optional ZFS pool
Expansion	One disk at a time (RAIDZ expansion)	One disk at a time, natively
Apps / containers	Docker + VMs, app catalog	Docker + VMs, large community store
Hardware / RAM	ZFS prefers more RAM	Lighter; runs on modest hardware
Ease of use	Powerful, steeper curve	Friendliest for beginners
Best for	Integrity-first, like-sized builds	Mixed-drive media/home servers

Read it down and the split is clean: TrueNAS optimises for free, bulletproof integrity; Unraid optimises for flexibility and a gentle learning curve.

Which should you run?

There's a right answer for your pile of drives, not a universal one.

Choose Unraid if your disks are different sizes, you want the gentlest possible on-ramp, you're building a media or general home server, and a one-time license doesn't bother you. It's hard to beat for a mixed-drive homelab.

Choose TrueNAS SCALE if you want $0 cost and ZFS-grade integrity for data you can't re-download — family photos, documents, backups — and you can group like-sized disks (or lean on RAIDZ expansion from here on). Whichever you pick, remember that neither parity nor ZFS is a backup: keep a real off-box copy of anything that matters.

Either OS can host your media library and containers. Many homelabbers actually run the NAS as a pool or VM under a hypervisor — our Proxmox homelab guide covers that layout — and expose its web apps safely behind a reverse proxy. Lock down the NAS accounts with the same care as any login, the way our browser privacy guide lays out, and you've got storage you can trust for years.

FAQ

Is TrueNAS really free?

Yes. TrueNAS SCALE is open-source with every feature unlocked at no cost. There's no paid tier gating capacity, apps, or integrity features.

Can Unraid mix different-sized hard drives?

Yes — that's its signature feature. A 4 TB, 8 TB, and 14 TB drive can share one array without wasting capacity. Your parity drive just has to be at least as large as your biggest data drive.

Can TrueNAS expand a ZFS pool one disk at a time now?

Yes. OpenZFS 2.3 added RAIDZ expansion, now supported in TrueNAS SCALE, so you can grow a RAIDZ pool by adding a single disk — the flexibility ZFS historically lacked.

Does the Unraid license expire?

No. All Unraid tiers are perpetual — the software keeps working forever. Only software updates are time-limited on the Starter and Unleashed tiers (one year); the Lifetime tier includes updates indefinitely.

Which is better for a beginner?

Unraid, generally. Its interface and setup are the most approachable of any NAS OS, and its community app store makes adding services simple. TrueNAS is more powerful but has a steeper learning curve.

Which is better for a home media server?

Unraid is a favourite for media because mixed-drive expansion suits a library that grows over time. TrueNAS works well too, especially if you value ZFS integrity and buy disks in matched sets.