DIY NAS Build 2026: Two Parts Lists + Build vs Buy
· Last verified July 2026
If you've built a gaming PC before, a NAS is not a harder project; it's a different one, with the emphasis shifting from clock speed and graphics to drive count, power draw, and the operating system that will run untouched for years. The reason people build instead of buy usually comes down to two things a sealed appliance can't give you: the freedom to run whatever OS you want, and a parts list you can grow one component at a time. Below you'll find both builds spelled out in full, a realistic total cost for each, and a plain answer to the question everyone actually asks first, which is whether building is even worth it over a modern Ugreen or Synology.
Build vs buy: the honest verdict first
The uncomfortable truth is that at two to four bays, a prebuilt NAS usually wins on price once you add up a case, a motherboard, RAM, and a boot drive; a modern Ugreen or Synology arrives assembled, warrantied, and with a support line, and the DIY parts total often lands within a few dollars of it before you've screwed in a single drive. DIY starts to pull clearly ahead at six bays and beyond, because a large turnkey chassis carries a steep premium while a DIY six-to-eight-bay build reuses the same board and case whether you fill three bays or eight. That is why this guide draws the line where it does, and why the small build below is framed as "the one to skip if a 4-bay Ugreen already fits."
Where DIY wins unconditionally is flexibility and control. You choose the operating system (Unraid, TrueNAS Scale or OpenMediaVault, all longtime homelab favourites) instead of accepting whatever the vendor ships, and you can swap a failing PSU or add a network card without waiting on an RMA. What you give up is just as real: no single warranty covers the whole machine, nobody is on the phone at 2 a.m. when a rebuild stalls, and you own every driver quirk yourself. If that trade sounds tiring rather than fun, a prebuilt is genuinely the smarter call; the DIY route only pays off for people who want the control enough to be their own vendor.
The parts that actually matter in a NAS
A NAS asks for a different balance of components than a desktop, so it helps to know why each part is on the list before you start pricing them. The case is the part you'll live with longest and the one that decides your bay count, so a purpose-built NAS chassis with hot-swap trays, like the compact Jonsbo N2 or the larger Fractal Design Node 804, is worth prioritising over squeezing drives into a leftover ATX tower. The motherboard and CPU together set your power floor and your feature ceiling; for a file server you want plenty of SATA ports and low idle draw far more than raw cores. RAM is where the two builds diverge most, because ZFS is memory-hungry and benefits from error-correcting modules while a lightweight media build is happy on ordinary sticks.
Two parts confuse first-time builders and deserve a sentence each. A boot drive is separate from your storage array: the OS lives on a small SATA SSD or NVMe stick, never on the pool it manages, so a cheap 128-256 GB drive is plenty. And an HBA (host bus adapter) only enters the picture when you run out of motherboard SATA ports: it's an add-in card that presents drives directly to the OS, which is exactly what ZFS wants. If those two terms are new, our hardware RAID vs software RAID guide explains why the passthrough approach beats a classic RAID controller for a modern NAS.
Build 1: the low-power N100 file server (4-5 bay)
This is the build most people should start with: quiet, frugal, and more than fast enough for a household NAS that stores files, runs backups, and streams Plex to a couple of screens. The heart of it is Intel's N100, an efficient Alder Lake-N chip that pairs a low power envelope with Quick Sync video, so it can hardware-transcode a stream or two without a discrete GPU. Boards like the ASRock N100DC-ITX integrate the CPU, take DDR4, and even accept a DC power brick, which keeps the whole system's idle draw low enough that it barely moves your electricity bill; you can sanity-check the running cost in our NAS power consumption guide.
For the array, this build pairs beautifully with a compact five-bay chassis and mid-capacity CMR drives. A layout of five 8 TB drives in RAIDZ1 or a Synology-style single-parity array lands around 32 TB usable, which is a comfortable amount for photos, documents, and a media library; check the exact number for your drive mix in the calculator above, and see how many drives you actually need if you're still sizing it. Run this on OpenMediaVault or Unraid for the friendliest experience, and keep standard non-ECC RAM, because the ZFS memory concerns below don't apply when you aren't running ZFS. As a total picture, expect the non-drive parts (case, N100 board, 16 GB RAM, boot SSD, PSU) to sit in the same ballpark as a bare 4-bay prebuilt, so the deciding factor here really is whether you value the flexibility over the convenience.
Build 2: the ZFS/ECC workstation-class build (6-8 bay)
When the goal is long-term data integrity for a growing pool, the build changes shape: you want more RAM, ECC memory, and enough drive connectivity to fill six to eight bays without compromise. This is the natural home for ZFS on TrueNAS Scale, whose copy-on-write checksums catch silent corruption that ordinary RAID never notices; the mechanism is the same one covered in our bitrot and ZFS scrubbing piece. A larger quiet chassis like the Node 804 or a Jonsbo N3 gives you the bays and the airflow, and TrueNAS publishes its own hardware guide if you want to cross-check a board choice.
Two components define this build. The first is ECC RAM (memory that detects and corrects single-bit errors before they can be written to disk), which OpenZFS describes as recommended rather than mandatory; the widely repeated "scrub of death without ECC" story is a myth, and we unpack the whole debate in ECC RAM for NAS and ZFS. The second is the HBA: once you pass the four-to-six SATA ports a typical board offers, an LSI 9300-8i flashed to IT mode adds eight drives and hands each one straight to ZFS. For the layout itself, six 12 TB drives in RAIDZ2 (double parity, so any two drives can fail) gives roughly 48 TB usable with a safety margin that matters as capacities climb; if you're weighing single versus double parity, our RAID levels overview lays out the trade-offs. The bonus knob for the technical crowd is that flashing a stock LSI card from IR to IT firmware is what turns it from a hardware RAID controller into the plain pass-through HBA ZFS actually wants; it's a one-time flash, well documented, and the single most common upgrade on second-hand server cards.
The parts list: budget, performance, premium
Which OS should run on it?
The operating system matters as much as the hardware, because it decides how you pool drives, how you snapshot, and how much day-to-day maintenance you sign up for. Unraid is the friendliest starting point and lets you grow the array one drive at a time with mixed sizes, which suits a media server that expands unpredictably. TrueNAS Scale is the answer when data integrity is the whole reason you're building, giving you ZFS with checksums and snapshots at the cost of committing to matched drives inside a vdev. OpenMediaVault is the tight-budget choice that runs happily on the N100 build and leaves you in a normal Debian shell rather than an appliance.
Rather than restate the full comparison here, our NAS operating-system hub and the detailed Unraid vs TrueNAS vs OpenMediaVault breakdown cover licensing, RAID options, and performance side by side. The short version for these two builds is that Unraid or OpenMediaVault fits Build 1, while TrueNAS Scale is the natural partner for the ECC-equipped Build 2.
Recommendation
If you want a quiet, low-power NAS for files, backups, and light Plex, build the N100 mini-ITX machine on OpenMediaVault or Unraid with five 8 TB CMR drives, but be honest with yourself first, because if a 4-bay Ugreen already covers you, the prebuilt is the smarter buy. If you're building for the long haul with a pool that will grow past 48 TB, go with the ZFS/ECC 6-8 bay build on TrueNAS Scale, an LSI 9300-8i in IT mode, and six 12 TB drives in RAIDZ2 for double-parity peace of mind. And if the words "IT-mode flash" and "vdev" make you want to close the tab, that's the clearest signal that a turnkey box, not a parts list, is the right answer for you, and there's no shame in it.
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