Unraid
Unraid
Drive-independent parity, mixed drive sizes, the best Docker + VM ecosystem in the NAS world. The closest thing to "Synology DSM for DIY" — with a paid license and a passionate community.
Overview
Unraid runs from a USB stick on any x86-64 PC. Each data drive holds a complete XFS, BTRFS, or ZFS filesystem with its own files (no striping). A parity drive stores XOR parity calculated from the data drives' raw blocks. A drive failure rebuilds onto a replacement; meanwhile other drives remain readable. Docker, KVM virtualization, and Community Applications come built-in.
Pros
- Each disk holds its own filesystem — single failure only loses that drive
- Mixed drive sizes work natively (parity must be ≥ largest data drive)
- Add disks one at a time as you grow — no rebuild from scratch
- Excellent Docker / Plex / Jellyfin ecosystem
- Built-in KVM virtualization, GPU passthrough
- USB-boot OS — runs on tiny appliances or old PCs
- Active community forum, plugins, regular updates
- ZFS pool support since 6.12
Cons
- Paid license ($49-$249), no free tier
- Single-disk read speed (no striping) — slower sequential reads
- Parity-write penalty: every write touches the parity drive
- Closed-source core (plugins are open)
- License keyed to USB stick — stick failure = re-activation
- Smaller mobile-app catalogue than Synology
- No native HA / failover
Good fit if you
- Want a Plex / Jellyfin / media-heavy NAS
- Run lots of Docker containers
- Have mixed drive sizes or plan gradual upgrades
- Care about per-drive isolation
- Want VMs and containers on the same box
- Comfortable with a forum-driven community
Bad fit if you
- Need maximum sequential read speed
- Want free / 100% open source
- Need polished mobile apps for backups
- Need HA / clustering / enterprise replication
Pricing & licensing
Starter $49 lifetime (6 storage devices), Unleashed $109 lifetime (unlimited devices), Lifetime $249 (unlimited devices + free OS upgrades). License tied to the USB boot stick's GUID.
Hardware
Runs on any x86-64 PC with a USB boot stick. Minimum: 4 GB RAM and one drive. Sweet spot: 6-8 core CPU, 16-32 GB RAM, 4-8 drive bays, SSD cache pool.
Typical use cases
Media servers (Plex, Jellyfin), self-hosted apps (Nextcloud, Home Assistant, *arr stack), VM lab combined with storage, mixed-drive long-term archive, gradual home NAS expansion.