NAS · Head to head

Ubiquiti UNAS 2 vs Ubiquiti UNAS 4

Full NAS comparison in 2026

Updated October 2026
Data from Amazon and official Ubiquiti site.
2026 verdict
These two Ubiquiti NAS go head to head, and the Ubiquiti UNAS 2 edges it as the simpler, more affordable box.
Ubiquiti UNAS 2
Winner
Ubiquiti UNAS 2
$248.20

Last recorded price

Buy on Amazon USA
It is a two-bay desktop that covers mirroring, snapshots, a 2.5 GbE port, a front USB-C port and PoE power, which is all a file share inside a UniFi network usually needs. The Ubiquiti UNAS 4 moves to four bays plus two M.2 NVMe slots and opens the door to RAID 5 and RAID 6, so it is the one to take once a mirror is no longer enough. Both run the same UniFi Drive software, so the real decision is how many drives you will actually fill.
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FeatureUbiquiti UNAS 2Ubiquiti UNAS 4Winner
Price$248.20$574.99Ubiquiti UNAS 2
Rating2.14.6Ubiquiti UNAS 4
Memory Capacity4 GB4 GBTie

What the differences mean

Drive bays

The Ubiquiti UNAS 2 holds two 3.5-inch drives in a shared tray and the Ubiquiti UNAS 4 holds four. Two bays mean a mirror, so half the raw capacity is spent on the copy; four allow RAID 5 and RAID 6, where one or two drives cover the whole array.

M.2 NVMe slots

The UNAS 4 adds two M.2 NVMe slots that the UNAS 2 does not have, used to cache repeated reads in front of the spinning disks. On a photo library or a busy media share that cache is what keeps browsing responsive.

Redundancy

The UNAS 2 offers mirroring only. The UNAS 4 supports RAID 5 and RAID 6, so it survives one or two drive failures while keeping most of the raw capacity usable, which is the point of moving to four bays.

Power over Ethernet

The UNAS 2 runs on a single PoE cable at 60W. The UNAS 4 needs a PoE+++ supply of about 90W, more than many switches deliver per port, so a single-cable install is easier on the smaller unit.

Which one to buy if

  • you only need a mirrored file share
    Ubiquiti UNAS 2

    The UNAS 2 covers two-bay mirroring, snapshots and remote backup in a smaller, quieter desktop.

  • you want parity so a drive failure does not halve your space
    Ubiquiti UNAS 4

    The UNAS 4 unlocks RAID 5 and RAID 6, which the two-bay UNAS 2 cannot offer.

  • you want NVMe caching for a large media or photo library
    Ubiquiti UNAS 4

    The UNAS 4 has two M.2 NVMe slots; the UNAS 2 has none.

  • you want the lowest-power single-cable install
    Ubiquiti UNAS 2

    The UNAS 2 draws up to 60W over PoE, where the UNAS 4 needs about 90W.

Upgrading from the Ubiquiti UNAS 2?

Moving up from the Ubiquiti UNAS 2 to the Ubiquiti UNAS 4 swaps a two-bay mirror for four bays and two M.2 NVMe slots, which is what unlocks RAID 5 and RAID 6 and a larger pool. Network and single-cable PoE management stay the same, as does UniFi Drive, so the change is capacity and redundancy rather than software. The UNAS 4 also wants more power over that one cable, so check the switch. If a mirror already holds everything you need, the UNAS 2 stays enough; if the array is filling up or you want parity instead of a copy, the four bays are the reason to move.

Price history compared

Every price change of both, in the same store, so the gap between the two lines is what one costs more than the other.

  • Ubiquiti UNAS 2
  • Ubiquiti UNAS 4

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Frequently Asked Questions

Which is better overall: Ubiquiti UNAS 2 or Ubiquiti UNAS 4?

The Ubiquiti UNAS 2 for a simple mirrored file share, since it is smaller, quieter and more affordable and covers snapshots and remote backup. The Ubiquiti UNAS 4 is the upgrade pick once you want four bays, RAID 5 or RAID 6 and NVMe caching.

What is the biggest difference between the Ubiquiti UNAS 2 and the Ubiquiti UNAS 4?

Bay count. The Ubiquiti UNAS 2 has two bays for mirroring only, while the Ubiquiti UNAS 4 has four bays plus two M.2 NVMe slots, which enables RAID 5 and RAID 6 and a much larger usable pool.

Do the Ubiquiti UNAS 2 and UNAS 4 run the same software?

Yes. Both run UniFi Drive and are managed in the UniFi console with snapshots and remote backup. Neither runs Docker containers, virtual machines or a third-party app store.

Which one is easier to power over Ethernet?

The Ubiquiti UNAS 2 draws up to 60W on a PoE cable, while the Ubiquiti UNAS 4 needs a supply of about 90W. Check that your switch can deliver the higher PoE class before planning a single-cable install on the UNAS 4.

Who should buy the Ubiquiti UNAS 2?

A UniFi user who wants a compact desktop share with mirroring, snapshots and one PoE cable, and does not need four bays or NVMe caching.

Who should buy the Ubiquiti UNAS 4?

A UniFi user whose data has outgrown a mirror, or one who wants RAID 5 or RAID 6, NVMe caching and more room to grow.

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