Unraid vs TrueNAS vs OpenMediaVault: Which NAS OS Should You Choose?

Quick Summary (TL;DR): Choose Unraid if you want a friendly all-in-one home server, expect to add different-sized hard drives over time and value straightforward app and VM management. Choose TrueNAS Community Edition if storage integrity, ZFS snapshots, replication and a deliberately planned disk layout are the priority. Choose OpenMediaVault (OMV) if you want a free, relatively lightweight Debian-based file server and are comfortable assembling extra features through plugins or Linux administration. None is automatically the fastest or safest: the disks, pool layout, backup plan and your ability to maintain the system matter more than the logo. Our default for a growing media/home-lab box is Unraid; for a dedicated ZFS NAS AliExpress price it is TrueNAS; for a budget file server it is OMV.

Specification-based comparison, checked against official project documentation on 11 October 2026. This is not a hands-on benchmark or a claim that the three systems were tested on identical hardware. Software versions, licence terms and plugin availability can change; follow the linked documentation before installing.

Unraid vs TrueNAS vs OpenMediaVault: Quick Comparison

Decision factor	Unraid	TrueNAS Community Edition	OpenMediaVault 8
Best fit	Mixed-drive media NAS AliExpress price plus apps and VMs	ZFS-first storage server, snapshots and replication	Low-cost file sharing with Debian flexibility
Software price	Paid perpetual licence; updates policy varies by tier	Free Community Edition	Free, open source
Typical storage design	Independent-disk parity array and/or ZFS/Btrfs pools	ZFS pools made from vdevs	Individual disks, Linux mdadm RAID, ext4/Btrfs; optional ZFS plugin
Different-size HDDs	Excellent in classic array, subject to parity sizing	Possible, but vdev layout determines efficiency	Possible individually; mdadm RAID wastes excess capacity on larger members
Data checksums and repair	Full ZFS pool supports them; classic parity array is different	Core ZFS strength when redundant and configured properly	Depends on filesystem and layout; ext4/mdadm is not end-to-end ZFS
Containers	Integrated Docker management	Integrated Apps and custom Docker Compose support	Available through extra components/plugins; not the same default experience
Virtual machines	Integrated VM manager	Virtualisation capabilities vary by release; check current support	Possible through Debian tools, not a central OMV strength
Boot approach	USB flash or supported internal boot on Unraid 7.3+	Separate boot device; SSD recommended	Separate OS drive recommended; Debian-based
Learning curve	Usually easiest for mixed-use DIY NAS AliExpress price	More demanding storage planning	Simple shares; more hands-on for advanced services
Our verdict	Best flexibility	Best storage-centric design	Best minimalist budget option

These are architectural differences, not performance rankings. A four-drive TrueNAS system with 10GbE and a suitable ZFS layout can be excellent for editing, while a small Unraid box may be a better family media server. OpenMediaVault is not inherently slower because it is free: identical disks, network interfaces and workloads can erase many supposed OS-level advantages.

Start with Your Storage Plan, Not the Apps Catalogue

The biggest decision is how each operating system groups drives and protects data. A NAS AliExpress price with four identical drives is a different purchase from one assembled over several years using 8TB, 12TB and 16TB disks. The software should fit the second upgrade, not merely the first installation.

Unraid classic array: independent data disks plus parity

In the classic Unraid array, files are stored on individual data disks rather than striped across all drives. One or two parity disks can protect the array against the corresponding number of disk failures, provided the parity disks meet the capacity rules. You can often add one appropriately sized data disk without rebuilding an entire striped RAID layout. This is the main reason Unraid is attractive for gradually growing media collections.

The trade-off is that a single large file on one array disk is generally bounded by that disk’s performance, and parity-protected writes have overhead. An SSD or NVMe pool is the usual place for app data, databases, downloads and VM disks. Do not confuse the array with a multi-disk ZFS pool: Unraid supports both, but they behave differently.

TrueNAS: ZFS vdevs determine capacity and fault tolerance

TrueNAS organises disks into ZFS virtual devices (vdevs), which form a pool. Mirrors and RAIDZ provide different balances of redundancy, usable capacity, random I/O and expansion. ZFS checksums stored data and metadata; with a healthy redundant layout it can often repair corrupted blocks using a valid copy. Scrubs help discover errors before a second disk fails.

Modern TrueNAS supports adding disks to existing RAIDZ vdevs through RAIDZ expansion, so the old statement that RAIDZ can never expand by one disk is outdated. However, this does not make a ZFS pool identical to Unraid’s mixed-size array: old block geometry, vdev redundancy and capacity planning still matter. The official documentation explains that an expanded RAIDZ vdev may have less usable space than a freshly created one of the same width.

OpenMediaVault: Linux disks and mdadm RAID

OMV exposes familiar Linux storage choices through a web interface. Ext4 and XFS are straightforward for a single data disk or an mdadm array; Btrfs offers additional capabilities, including snapshots of shared folders in the current OMV interface. OMV uses mdadm for software RAID 1, 5, 6 and 10, subject to its documented constraints. ZFS is not a native built-in filesystem in the standard OMV web interface: a third-party omv-extras plugin is required, and that extra dependency needs maintenance.

The practical distinction is control versus integration. OMV can be an excellent file server without the extra layers, but adding sophisticated application orchestration, ZFS or virtual machines creates more components to understand and troubleshoot.

Parity, Checksums and Backups Are Three Different Things

Protection	What it helps with	What it does not solve
Parity / RAID redundancy	Keeps data accessible after the supported number of drive failures	Deletion, ransomware, theft, fire, incorrect writes, too many failures
Checksums with redundant ZFS copies	Detects silent corruption and can repair from a good copy	A deleted file or corrupted application database without a retained version
Snapshots	Restores previous versions after mistakes or some malware incidents	Loss of the entire NAS AliExpress price or all storage in the same pool
Independent backup	Provides a separate recovery copy if the source is damaged	Nothing unless jobs, credentials, retention and restore tests actually work

A parity check can confirm parity consistency without establishing that the original file was semantically correct. A checksum can tell you that data changed unexpectedly but cannot create missing redundancy. A snapshot is not a backup if it lives only on the failed storage pool. For family photos or business records, use a second NAS, offline USB rotation or a suitable off-site destination in addition to local redundancy.

For practical retention and off-site protection, see our 3-2-1 NAS backup plan and the external NAS backup drive guide.

Capacity Examples: Four Equal Drives and Four Mixed Drives

These examples use manufacturer decimal TB, ignore filesystem overhead and reserve no free space for healthy operation. They illustrate layout maths, not measured capacity or speed. TrueNAS/OMV configurations below assume a single conventional RAIDZ/mdadm group rather than a collection of independent volumes.

Four 12TB HDDs	Nominal protected data capacity	Fault tolerance	Important condition
Unraid, one parity disk	36TB	One failed disk	One 12TB parity plus three 12TB data disks
Unraid, two parity disks	24TB	Two failed disks	Two parity disks plus two data disks
TrueNAS, RAIDZ1	About 36TB before overhead	One failed disk	One four-wide RAIDZ1 vdev
TrueNAS, RAIDZ2	About 24TB before overhead	Two failed disks	One four-wide RAIDZ2 vdev
OMV, mdadm RAID5	About 36TB before overhead	One failed disk	Four-disk Linux RAID5
OMV, mdadm RAID6	About 24TB before overhead	Two failed disks	Four-disk Linux RAID6

Mixed HDD set: 12 + 12 + 8 + 8TB	Nominal usable data	Why
Unraid classic array, one 12TB parity	28TB	Other drives contribute 12 + 8 + 8TB independently
TrueNAS one RAIDZ1 vdev	About 24TB before overhead	All four members contribute roughly 8TB each to this vdev
OMV one mdadm RAID5	About 24TB before overhead	RAID member capacity is effectively limited by the smallest drive
Separate OMV volumes, no RAID	40TB, without redundancy	Full individual capacity but no disk-failure protection

For mixed-size storage, Unraid has a clear capacity advantage in this specific scenario. But do not treat the table as a recommendation to use a single parity disk with irreplaceable data: large-drive rebuilds take time, and backup remains essential. For a fixed set of matched disks, TrueNAS or mdadm can make equally sensible use of the capacity.

Unraid: Best for a Growing Home Server with Mixed Disks

Unraid is especially persuasive when your server will do several jobs: store films and photos, run Jellyfin or Plex, host a few Docker services and perhaps run a Linux VM. Its management interface brings array assignment, shares, containers, VMs and monitoring into one place. This saves integration effort, though it does not remove the need to understand paths, permissions, backup jobs and the security of each service.

Where Unraid earns its licence fee

Incremental capacity: add data drives to the classic array without purchasing a complete matched set, subject to the current device limit and parity sizing.
Clear split between bulk and fast storage: use HDDs for media and an SSD/NVMe pool for frequently written application data.
One-box homelab: integrated Docker and VM tools are convenient for users who do not want a separate hypervisor.
Multiple storage modes: Unraid also supports ZFS and Btrfs pools; choosing the classic array is optional, not a system-wide restriction.

What you give up

A parity array is not a substitute for ZFS data integrity. If you require end-to-end checksums and self-healing across a redundant storage set, create a proper ZFS pool and accept its layout rules. Also budget for the licence and consider what happens when the included update period ends. A perpetually licensed installation does not imply perpetual access to all future releases.

Do not buy a large cache SSD assuming every write is instantly protected. A single-device cache/pool can be a single point of failure until data is copied elsewhere; for important app data, use a redundant pool and independent backups. Keep databases and VM disks on fast storage rather than assuming a parity HDD array will match SSD random I/O.

Boot media has changed

Older guides say Unraid must boot from USB. Current official documentation states that Unraid 7.3 and later can also use a supported internal boot device, with the applicable onboarding and licensing requirements. USB boot remains supported, and a USB device with a unique GUID is still part of the initial installation path described by Unraid. Check your target release and TPM/internal-boot eligibility rather than following an old blanket rule.

If this is your chosen route, the dedicated first Unraid server build guide covers the hardware and disk-layout decisions without turning this comparison into an installation tutorial.

TrueNAS: Best for a Dedicated, Integrity-Focused Storage Server

TrueNAS Community Edition is the natural choice when the NAS exists mainly to serve reliable storage to computers, hypervisors and applications. Its ZFS-first design makes datasets, snapshots, scrubs, replication and controlled sharing central concepts rather than add-ons. The benefit is strongest when you deliberately choose the vdev topology before putting data on the system.

Current version and hardware baseline

As checked on 11 October 2026, the TrueNAS software-status page lists 25.10.7 as the recommended stable maintenance release for general users, while newer development/RC builds are not the conservative default for valuable data. The TrueNAS 25.10 hardware guide specifies a 64-bit x86 processor, 8GB RAM and a dedicated boot device, recommending a 16GB SSD rather than a USB stick. Treat 8GB as a basic floor, not a promise that a large app-heavy NAS will perform well on 8GB.

For a new four-to-eight-drive ZFS NAS, 16GB RAM is a sensible planning starting point and 32GB or more can be worthwhile for demanding applications, many clients, VMs or large working sets. Those figures are purchasing guidance, not a fixed ZFS rule of 1GB per terabyte. ECC memory is desirable where the platform supports it, but TrueNAS documentation does not make ECC mandatory for all community installations.

Snapshots and replication are valuable, but design them

A ZFS snapshot preserves a point-in-time view of a dataset and is usually cheap to create, but retained changes consume storage. Replication to a second system gives the snapshots a separate failure domain. Plan snapshot frequency, retention and restore rights before enabling them: thousands of snapshots without an understood retention policy can complicate management, and snapshots cannot recover files from a destroyed pool without an independent copy.

Where TrueNAS is less forgiving

A poorly chosen vdev layout is expensive to undo. Expanding RAIDZ by one drive is now supported, but changing redundancy level or completely reorganising vdevs is not the same as adding a random spare disk to an Unraid array. Use matched drives where practical, ensure the storage controller exposes the actual disks rather than hiding them behind a hardware RAID volume, and verify the backup before creating or altering a pool.

For the installation path, use our DIY TrueNAS installation and pool-planning guide.

OpenMediaVault: Best for a Lean, Free Debian NAS

OpenMediaVault 8 runs on Debian 13. It supplies web-managed shared folders, SMB/NFS-related services, SMART monitoring, updates, users, permissions and storage management without charging a NAS licence. The project’s published minimum memory is only 1GiB, although its own guidance points to more RAM for a comfortable modern system. For a basic two-disk backup/file server, the lighter footprint can make refurbished hardware viable.

Keep the base installation simple

A small OMV build can use a dedicated SSD for Debian/OMV and one or two data HDDs formatted with ext4. Add an mdadm mirror if availability during a disk failure matters, or keep the disks independent if the second disk is a genuinely separate backup target. Use the OMV web interface to create and mount the filesystem, define shared folders and grant access; avoid editing the same managed services behind OMV’s back unless you know how its configuration database and deployment work.

Plugins change the maintenance equation

Docker/Compose workflows, ZFS and other advanced services can be added, but availability and support depend on the current plugin and OMV release. The official OMV filesystem documentation explicitly identifies ZFS as a third-party plugin route, not an ordinary built-in format option. OMV 8 also has a Kubernetes/K3s plugin, but that is not a reason to assume it provides the same container management workflow as Unraid or TrueNAS. Choose one supported approach and document how it is updated and backed up.

OMV is appealing to Linux users who would otherwise build a Debian server by hand. It is less compelling when you want a polished all-in-one app marketplace and little shell administration. Free software may still cost more of your time; that is a maintenance judgement, not a measurable subscription charge.

Docker, Media Servers, Home Assistant and Virtual Machines

Workload	Unraid	TrueNAS	OpenMediaVault
Plex / Jellyfin	Integrated Docker workflow; fast pool recommended for metadata	Apps or custom Compose; plan separate app dataset	Docker/Compose through a supported add-on or manual Debian administration
Immich photo server	Containers plus separate backed-up photo storage	Apps/Compose with deliberate dataset and database placement	Possible, but container stack and upgrades are more manual
Home Assistant	VM or container possible; choose based on required HA features	VM/app possibilities depend on version and hardware	Container or VM through additional tooling; not an appliance-style HA OS
Several Linux/Windows VMs	Integrated manager; CPU/RAM and IOMMU still matter	Check the chosen release’s VM feature set and device support	Requires separate Debian virtualisation tooling; less integrated
Pure SMB/NFS backup target	Works, but you pay for broader platform	Excellent fit for snapshots and replication	Excellent low-cost fit for simple shares

Do not conflate running Home Assistant Container with running Home Assistant OS. The former does not provide the full Home Assistant OS/Supervisor experience; the latter normally belongs in a VM or on dedicated hardware. If Home Assistant is the primary objective, compare deployment methods in Home Assistant OS vs Docker vs Proxmox rather than selecting a NAS OS purely for one application.

For containers that store important data, identify the persistent volume or host path, confirm file ownership and back up both the application configuration and the underlying dataset. Copying a container image is not a backup of its database. For hardware transcoding, check the exact CPU/iGPU, container device mapping, codec and any required Plex subscription; the NAS operating system alone does not guarantee acceleration.

Hardware Requirements and What to Buy

Component	Unraid buying guidance	TrueNAS buying guidance	OMV buying guidance
CPU	Modern 64-bit x86; more cores for simultaneous VMs/transcodes	64-bit x86; prioritise storage controller and ECC support where available	Debian-supported x86-64 or suitable ARM; modest CPU is fine for file serving
RAM	8–16GB is a practical small mixed-use start; add for VMs/apps	8GB official basic minimum; plan 16GB+ for a growing home NAS	1GiB published minimum; 4–8GB+ is more comfortable
Boot device	USB flash or supported internal boot with Unraid 7.3+	Dedicated SSD recommended; 16GB listed in 25.10 guide	Separate SSD/OS drive recommended; Debian 13 support
Data controller	Expose disks directly; plan enough SATA/HBA ports	HBA/JBOD access to individual disks; avoid opaque hardware RAID	Linux-compatible SATA/HBA; mdadm expects visible disks
Fast app storage	SSD/NVMe pool strongly useful	Separate suitable app dataset/pool where workload justifies	Optional SSD for appdata, not mandatory for basic SMB
Network	1GbE fine for basic media; 2.5/10GbE if workload demands	10GbE can help multi-client or SSD-backed workloads	Network choice driven by workload, not OS
UPS	Useful for clean shutdown and cache safety	Strongly recommended for controlled ZFS shutdown	Useful for mdadm/filesystem and clean shutdown

The most expensive mistake is buying a compact case or mini PC with no practical path to the number of directly attached, reliably cooled drives you intend to use. Check SATA lanes, HBA compatibility, PCIe slot bandwidth, drive power on spin-up, fan airflow and physical access. A cheap motherboard with four SATA ports can become expensive if it forces an awkward expansion card or replacement case after the first upgrade.

If you are still choosing hardware, start with DIY NAS vs prebuilt NAS: complete build and running costs and HBA vs PCIe SATA card vs motherboard ports.

What Does Each NAS OS Cost Over Five Years?

Software prices below were checked on 11 October 2026 using the official Unraid checkout and licensing FAQ. These are US-dollar licence figures, before any regional taxes or exchange-rate conversion; they are not UK retail hardware prices. Unraid’s Starter licence covers six attached storage devices under its counting rules, while Unleashed and Lifetime remove the licence-imposed device count. All paid tiers are perpetual licences. Starter and Unleashed include one year of updates; the optional annual update extension is currently $36.

OS / licence	Initial software cost	Five years with no optional renewal	Five years with four annual extensions after year one
Unraid Starter (up to six licensed devices)	$49	$49	$193
Unraid Unleashed (no licence device cap)	$109	$109	$253
Unraid Lifetime (no licence device cap)	$249	$249	$249 — lifetime updates included
TrueNAS Community Edition	$0	$0	$0
OpenMediaVault	$0	$0	$0

For example, $109 + (4 × $36) = $253 for an Unleashed owner who chooses to extend updates in years two through five at today’s rate. A Starter owner would pay $49 + (4 × $36) = $193 under the same assumption. These are planning scenarios, not a promise that extension fees stay unchanged. Skipping renewal leaves the existing licensed version usable, but updates become limited by the project’s documented release-support policy; this has security implications for an internet-connected system.

The software fee is only a small part of a storage server’s cost. Compare the full build: enclosure, motherboard, CPU, RAM, boot SSD, data HDDs, optional cache SSD, HBA, network upgrades, backup drive, UPS and electricity. A platform with no licence can still be the more expensive system if it needs additional RAM or a complete replacement drive set to meet your intended layout.

An electricity example without invented benchmarks

Suppose your measured at-the-wall average system power is 30W and electricity costs an illustrative £0.30/kWh. That is 0.030kW × 24 × 365 = 262.8kWh per year, or £78.84/year; over five years it is £394.20 before price changes. At 50W, the same calculation is 438kWh/year and £131.40/year. These are transparent calculations, not measured Unraid, TrueNAS or OMV consumption figures. Disk count, CPU, idle behaviour, fan speed and HBA power matter much more than a claimed OS power ranking.

Annual electricity (kWh) = average measured watts / 1000 × 24 × 365
Annual cost = annual kWh × your actual tariff
Five-year ownership = hardware + disks + backups + UPS + licences + electricity + replacements

A power meter, measured idle load and your actual tariff will produce a better estimate than any generic “NAS OS watts” chart. Consider the impact of drive spin-down only if it is compatible with your workload and maintenance policies.

Security, Updates and Remote Access

All three systems can be secured well, and all can be made unsafe. Put the administration interface on a trusted management network, require strong unique credentials, keep packages and apps updated, and expose remote access through a well-configured VPN rather than forwarding NAS admin or SMB ports to the public internet.

Unraid: track whether your current release remains supported under your update entitlement, and keep container images, plugins and the boot configuration backed up.
TrueNAS: use the project’s software-status recommendation for important systems, restrict dataset and SMB permissions, and check snapshot/replication alerts.
OMV: keep Debian and OMV packages patched, document any third-party repository or plugin, and avoid installing conflicting web/server management software outside OMV.
All three: disable unnecessary services, protect SSH, use separate service credentials, and test restoring data without depending on the original NAS.

A VLAN can limit lateral movement from untrusted IoT devices, but it will not fix permissive share credentials. If the server shares a home network with cameras and ESPHome nodes, see VLAN design for Home Assistant, IoT, NAS and cameras. For off-site access, compare VPN and vendor-relay options in remote NAS access: Tailscale, WireGuard or manufacturer apps.

Migration: Do Not Assume You Can Reuse the Existing Array

Changing the NAS operating system is not the same as changing the desktop theme. The storage metadata, partitioning and pool layout may be incompatible, and an installer may offer to wipe drives. Always make and verify a separate backup before experimenting with an imported pool or formatting an old disk.

Move	Safer approach	Common trap
Windows PC / USB disk to OMV	Copy files to new mounted data volume; verify permissions and checksums	Assuming an external NTFS disk is a permanent ideal Linux NAS layout
Unraid classic array to TrueNAS ZFS	Build a new ZFS pool on suitable disks; copy and verify data	Expecting TrueNAS to import Unraid parity as a ZFS pool
TrueNAS ZFS to Unraid ZFS	Read exact import compatibility and feature flags; retain verified backup	Assuming every newer ZFS feature flag is reversible
OMV mdadm to TrueNAS	Plan a separate destination pool and data migration	Expecting an mdadm RAID5 to be a TrueNAS RAIDZ1 vdev
Any platform with containers	Export application configuration and database, then restore to new paths	Moving image files but forgetting appdata, database or user IDs

Some ZFS pools can be imported between platforms when their feature sets are compatible, but that does not imply every TrueNAS configuration, dataset permission, encryption key or app path transfers cleanly. Likewise, a disk formatted as ZFS inside the Unraid classic array is not a whole ZFS pool with the array parity metadata. Plan a copy-and-verify migration unless the official procedure explicitly supports your exact layout.

Which NAS OS Should You Choose for Your Use Case?

Your situation	First choice	Why	When to reconsider
Media library grows one HDD at a time	Unraid classic array	Mixed-size drive efficiency and easy incremental growth	TrueNAS if ZFS integrity and matched pools are more important
Four or six matching drives, important shared files	TrueNAS	ZFS datasets, scrubs, snapshots and replication	Unraid ZFS pool if integrated apps/VMs are a stronger requirement
Old PC, one or two disks, simple SMB backups	OpenMediaVault	Free Debian-based file sharing with modest baseline	TrueNAS if you can supply the memory and want ZFS
Plex, Immich, downloads and several VMs	Unraid	Integrated app and VM management	TrueNAS if storage is primary and its current app/VM features fit
Dedicated backup destination with snapshots	TrueNAS or OMV	ZFS replication vs simple rsync/USB jobs	Choose based on required restore features and admin skill
Linux administrator wants maximum control	OpenMediaVault	Debian ecosystem and modular design	A plain Debian install may be simpler if OMV adds no value

For a first home NAS with two existing unequal drives, we would not automatically buy TrueNAS just because ZFS has an excellent reputation. A simple OMV file server with a proper backup, or Unraid if growth and applications are planned, may fit better. For a new six-bay NAS bought with matching CMR HDDs, TrueNAS deserves serious consideration before the disks are formatted. The correct answer follows the workload and upgrade plan.

A Practical Pre-Installation Checklist

Define the job: file shares, media streaming, surveillance, VM datastore, containers or a mix. Note which services must survive a single disk failure.
Inventory disks: exact model, capacity, recording technology, health, interface and whether any already contain irreplaceable data.
Choose a layout: classic parity array, ZFS mirrors/RAIDZ, mdadm mirror/RAID or independent disks. Calculate capacity and failure tolerance.
Choose hardware: check RAM, boot drive, SATA/HBA visibility, PCIe expansion, cooling, network and UPS.
Plan application data: decide where databases, media indexes, VM disks and container volumes will live.
Design backups: local snapshots where available, a separate copy, off-site or offline protection, retention and a test restore.
Install from official media: verify the downloaded release and identify the boot/data disks by serial number before any destructive operation.
Harden and monitor: credentials, updates, SMART alerts, scrub/parity schedules, backup alerts and shutdown behaviour.

Do a restore rehearsal with a non-critical folder before committing family photos. Verify not just that the NAS can be reached, but that a different computer can read the restored files and that permissions and timestamps are acceptable.

Common Problems and How to Avoid Them

Symptom	Likely cause	First useful check
New disks show less usable space than expected	Parity/vdev overhead, decimal TB vs binary TiB, smallest-disk constraint	Recalculate the exact disk layout and compare the OS capacity view
NAS file copies seem slow	1GbE link, HDD random I/O, parity write path, small files	Check negotiated link speed and measure network separately from disk
Container loses settings after an update	Data stored inside the disposable container layer	Check persistent host paths/volumes and database backup
ZFS pool cannot import on another host	Feature flags, missing disks, encryption keys or controller visibility	Check supported import procedure; do not force import on original-only copy
OMV share has permission denied	Unix ownership, ACLs and SMB account rights do not match	Inspect filesystem ownership, share ACL and effective user
Unraid cache is full	Mover/share placement or appdata growth	Inspect pool usage and share placement before deleting files
NAS unexpectedly reboots during a scrub	Power supply, RAM, cooling or controller problems	Check system logs, SMART, memory test and UPS events
Updates are blocked or risky	Unraid entitlement/release support or third-party OMV plugin compatibility	Review official release notes and make configuration backups first

If transfer speed is the problem, our 1GbE/2.5GbE/10GbE NAS troubleshooting guide separates network and disk bottlenecks before you buy new hardware.

Frequently Asked Questions

Is TrueNAS better than Unraid for data integrity?

A properly designed redundant ZFS pool gives TrueNAS strong checksum, scrub and self-healing capabilities. Unraid can also use a full ZFS pool, so the difference is storage layout, not a blanket claim that Unraid cannot use ZFS. The classic Unraid parity array is a different design and does not provide the same multi-disk ZFS self-healing behaviour.

Can I add one hard drive to TrueNAS?

Yes, supported TrueNAS releases include RAIDZ vdev expansion. Check the current procedure, pool health, capacity consequences and whether your specific layout qualifies. You cannot assume every change to a ZFS topology is supported, and adding a disk is not the same as changing RAIDZ1 into RAIDZ2.

Is OpenMediaVault completely free?

The core OMV software is free. You still pay for hardware, drives, backups and electricity; optional third-party services may have their own terms. Free licensing does not guarantee that advanced plugins are maintained for every future Debian/OMV release.

Does Unraid require a USB boot stick in 2026?

Not exclusively. Unraid 7.3 and later support a documented internal-boot path on suitable systems, while USB boot remains available. Verify the current installer, licensing and hardware requirements rather than relying on instructions written for Unraid 6.

Which one is best for Plex or Jellyfin?

Unraid is convenient for an integrated media server, particularly with a fast SSD pool for metadata. TrueNAS and OMV can also host media servers. Hardware transcoding depends on the actual CPU/GPU, driver support, container configuration and software requirements, not simply the NAS OS name.

Can I install any of these on a Raspberry Pi?

OpenMediaVault can be deployed on supported ARM systems using the documented Debian/Armbian route. Unraid and current TrueNAS Community Edition target x86-64 systems, so they are not straightforward Raspberry Pi OS replacements. USB-connected multi-drive RAID on a Pi also has power and reliability limitations; avoid treating a pile of USB disks as a production storage array.

Which OS is easiest to move away from later?

None guarantees one-click migration to a competitor. Standard network file shares and documented application backups improve portability. Independent data disks may make some recovery workflows simpler, while ZFS replication is valuable between compatible ZFS systems. Always retain a separate verified copy before changing OS or disk layout.

Verdict: Choose the Storage Architecture You Can Maintain

Unraid is our pick for a mixed-drive home lab that will grow over time and run multiple applications. TrueNAS is our pick for a purpose-built NAS where ZFS integrity, snapshots and replication lead the design. OpenMediaVault is our pick for a modest, free file server where the owner is happy to manage Debian and selected plugins. There is no universal winner, and paying for an OS does not replace a tested backup.

Make the decision using three questions: Will I add unmatched drives? Do I need ZFS-first storage and replication? Do I want integrated app/VM management or a lean Linux file server? Once those are answered, the right software is usually obvious—and the hardware budget can be spent where it improves the actual workload.