Unraid is a commercial Linux NAS operating system that protects a set of differently sized drives with up to two parity disks, without striping, so each disk stays independently readable. It also runs Docker containers and KVM virtual machines from the same web interface.
Our verdict on Unraid#
Unraid is worth paying for if your drives are mismatched and you plan to add one at a time, because the parity array does not stripe: lose more disks than you have parity for and you still read every surviving disk normally. The pricing changed in 2024 from lifetime-only to tiers, and the current tiers are Starter at 49 USD for up to 6 storage devices, Unleashed at 109 USD for unlimited devices, and Lifetime at 249 USD. Starter and Unleashed are perpetual licences that include one year of OS updates, after which a 36 USD annual extension is optional; skip it and you keep the version you have. Version 7.3 (May 2026) added two things worth upgrading for: internal boot from an SSD or NVMe instead of a USB stick, and TPM-based licensing so your key survives a boot device change. Current stable is 7.3.2, with 7.4 in beta. x86-64 only.
Who Unraid is for#
Choose it if
- Someone with a pile of mismatched drives who wants parity protection without buying matched sets
- A media server owner who values being able to spin down idle disks and read any single drive in another machine
- A home user who wants NAS, Docker and VMs in one paid product with a large community plugin ecosystem
Look elsewhere if
- You want write performance, because parity math makes array writes slower than any striped or ZFS pool
- You object to paying for a NAS OS, since TrueNAS and plain Debian do the same job for nothing
- Your hardware is ARM, which Unraid does not support
What running it actually looks like#
You need a USB flash drive with a unique GUID even if you intend to boot internally: the docs say a new server still starts from USB, and the onboarding wizard then offers flash boot or internal boot. Write the image with the Unraid USB Creator, boot the machine, and reach the WebGUI on port 80. Licensing binds to that USB GUID, or to the TPM if you move the licence with Tools then Registration on 7.3 or later. Assign a parity disk at least as large as your largest data disk, add data disks, optionally add a cache pool (which can be ZFS since 7.0), and start the array. Upgrades are done from the WebGUI; upgrade plugins first, because 7.2 auto-uninstalls several incompatible ones including Theme Engine and Dark Theme.
Resource profile#
- Memory
- 2048 MB idle, around 8192 MB in ordinary use. Unraid publishes no hard minimum; the OS runs from a root RAM filesystem and idles low, so these are estimates for a working server with a few containers rather than documented figures.
- CPU and acceleration
- Parity writes are the load: every write to the array reads and rewrites the parity disk, so sustained writes are slower than a striped array and pin a core. Transcoding wants Intel Quick Sync.
- Storage growth
- The array itself is your storage; note that a parity disk must be at least as large as your largest data disk, which sets the ceiling on future upgrades.
- Operational load
- 2 of 5, Light. Updates are one button and the config is a directory on the boot device, so restores are quick. What raises it above level 1 is plugin compatibility across releases and a monthly parity check that you should actually watch.
Figures describe a small single-household install and are the working assumptions behind our stack planner. Your numbers will differ with library size, user count and hardware. See methodology.
Data and backup surface#
The entire OS configuration is the config directory on the boot device: shares, disk assignments, users, Docker templates, VM XML and your licence key file. Back it up from Tools then Flash Backup, or copy the boot device contents; it is small and restoring it onto a new USB stick plus a licence replacement rebuilds the server. Application data lives in your shares, typically /mnt/user/appdata, which is what you actually need off-site. Docker images and the containers themselves are regenerable from templates. Note that parity is not a backup: it survives disk failure, not deletion, and there is no snapshot of the array itself.
Derived backup shape
File copy. Copy the config and data directories. Safe while running for anything that writes atomically.
Traps and surprises#
Pricing moved to tiers and device limits in 2024
The old Basic, Plus and Pro lifetime keys were replaced. Starter (49 USD) allows six attached storage devices total, excluding one eMMC and one USB. Unleashed (109 USD) and Lifetime (249 USD) allow unlimited devices, with the parity-protected array capped at 30 disks. Starter and Unleashed include one year of updates and then a 36 USD optional annual extension; without it you keep your current version indefinitely but get no new major releases.
You still need a USB stick to start a new server
Internal boot arrived in 7.3, but the documentation is explicit that a new server is started from a USB drive first, and the onboarding wizard then lets you choose internal boot. During the conversion the WebGUI may show "Array Offline"; do not restart or pull the flash drive while it configures. Internal boot also needs a device driven by a built-in driver: ahci, nvme, mmc, mpt3sas, mvsas, smartpqi or USB.
Plugins are auto-removed across major upgrades
Unraid 7.2 auto-uninstalls plugins that are incompatible with the new responsive WebGUI, including Theme Engine, Dark Theme, Dynamix Date Time and Flash Remount. Upgrade every plugin, especially Unraid Connect and the Nvidia driver plugin, before you upgrade the OS. Enabling RAIDZ expansion on a pool after upgrading can also block downgrading to an earlier Unraid version, so treat pool feature flags as one-way.
The parity disk sets your maximum drive size
Parity must be at least as large as the largest data disk. If your parity is a 12 TB drive, you cannot add a 20 TB data disk without first replacing parity and rebuilding it, which is a multi-day operation on large arrays during which you have no redundancy. Buy the biggest drive you can as parity first, not last, or plan for that rebuild window.
Array writes are slow by design
Every write to a protected array disk requires reading the old data and old parity and writing both back, so sustained write throughput is a fraction of the drive's rated speed. Turbo write mode trades power for speed by spinning up every disk. This is why nearly every Unraid setup puts container appdata and active downloads on a cache pool and lets the mover flush to the array overnight.
Specifications#
- Category
- Platforms and container management
- Licence
- Proprietary, perpetual per-device licence (Proprietary)
- Written in
- PHP / Slackware userland
- First release
- 2005
- Maturity
- Mature
- Datastore
- Flat configuration files on the boot device, loaded into a RAM filesystem at boot
- Default ports
80,443- Ships as
- USB flash boot, internal SSD or NVMe boot (7.3+)
- arm64 builds
- No
- Identity
- Native OIDC. Unraid 7.2 added optional OIDC single sign-on to the WebGUI via the built-in Unraid API; before that it was a single root password.
- Replaces
- Synology DSM, QNAP QTS, Windows Storage Spaces, Drobo
- Project site
- unraid.net
- Source
- github.com/unraid
- Documentation
- docs.unraid.net
Alternatives to Unraid#
Everything else in platforms and container management, closest in operational weight first.
| Tool | Ops load | Idle RAM | Licence |
|---|---|---|---|
| CasaOS | 2, Light | 300 MB | Apache-2.0 |
| Docker Engine | 2, Light | 120 MB | Apache-2.0 (Engine and Compose); Docker Desktop is proprietary |
| Podman | 2, Light | 40 MB | Apache-2.0 |
| Coolify | 3, Moderate | 1200 MB | Apache-2.0 |
| Dokploy | 3, Moderate | 900 MB | Apache-2.0, with DSAL 1.0 reserved for a /proprietary path |
| Komodo | 3, Moderate | 250 MB | GPL-3.0 |
Where Unraid comes up elsewhere#
Head to head
Sources#
Facts on this page were checked against the project's own material. Where a number is our own estimate rather than a published figure, the text says so.
Published . Last reviewed . Found something out of date? Tell us and we will fix it and log the change.