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TerraMaster T6-423 6-bay NAS Review: Impractical Design Meets Buggy Hardware

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The TerraMaster T6-423 is supposed to be a much more advanced NAS server compared to the previous F2-223. Among other things, it has six drive bays and two NVMe slots, rivaling the DS1621+, Synology's latest consumer-grade server of the same capacity.

But the extra drive bays are exactly this new server's downfall. They reveal its design flaw and the bugginess of TerraMaster's latest NAS operating system, the TOS version 5. The software is not ready to handle the many implied storage options.

As a result, while I recommended the F2-223, the T6-423 proved unbearable in my testing.

Here's the bottom line: If you're looking for a relatively low-cost, high-capacity, Mulit-Gig-ready server and intend to use it as a simple network storage space, the new server will work out and is even worth its friendly price tag of $700 (diskless). But avoid it at all costs if you want anything more. Go with a Synology instead.

Dong's note: I updated this post on January 26, 2023, to add information about the server's two M.2 NVMe slots, which were initially overlooked and erroneously omitted.

TerraMaster T6 423 NAS Server 1 1
The TerraMaster T6-423 NAS server includes screws to attach drives to its trays and a screwdriver. There are also extra rubber feet if you want to use the server in the horizontal position.

TerraMaster T6-423: A flawed NAS server

The T6-423 is the first high-capacity server from TerraMaster I've tested. With six drive bays, by design, it can handle all more advanced RAID configurations instead of only RAID 1 and RAID 0 in the case of a Dual-bay counterpart.

I was excited to try all that out and ran into one disappointment after another, starting with the server's physical design.

But first, it's worth noting that the new server runs TerraMaster's latest NAS operating system, TOS 5, and is generally the same as any other server running the same OS in terms of the setup process, interface, settings, and app. Overall, TOS 5 is a streamlined experience.

If you're unfamiliar with TerraMaster, open the drawer below for some generally positive highlights of the relatively new OS version.

TerraMaster TOS 5 in brief

This portion of the extra content is shared among TerraMaster servers.

Simple OS setup process

To make a TerraMaster server work, you'd first need to install the operating system, TOS 5, which is a simple process.

TerraMaster TNAS PC App
Install and run the TerraMaster TNAS PC desktop application, and you're almost there. Note the little "login" button that is shaped like a left arrow pointing to a door.

First, download and install the TNAS PC software—there are Windows, macOS, and Linux versions—on a computer and run it.

After a few seconds, the software will find the server in the network, as shown in the screenshots above. Now, you can use its IP address on a browser or click on the software's login button to launch the web-based setup wizard.

The wizard will work through a few self-explanatory steps to install the OS—directly from TerraMaster's server or via a local file—and everything else, including picking the RAID configurations, file format (BTRFS or EXT4), and the first user account.

You can start using a server with a single drive, but to use any RAID, you must have two or more. Generally, the setup process only allows for the creation of a single storage pool. When applicable, to have more pools, you need to use the Storage Manager—part of the Control Panel—once the server is up and running.

Depending on your Internet speed, the process will take five to thirty minutes. Then, you can log in to the server's web interface—via the same IP address—to customize it further.

TerraMaster NAS InitilizationTerraMaster NAS OS setup
The web-based initial setup part of TerraMaster's TOS 5

Robust web interface, flexible TRAID, and LDAP support

Unlike the clunky TOS 4.x, TerraMaster's TOS 5 is robust, similar to Synology DSM, and has a web-based user interface resembling a native operating system.

You can run multiple apps simultaneously and use the Control Panel to configure the router. Most importantly, there's the app store called App Center, which allows for the installation of more apps on the server.

TerraMaster F2 223 Apps Beta
Including beta versions, the TOS 5 has a few dozen of apps. Most of them are non-essential tools.

But first, it's worth noting that TOS 5 now has a flexible RAID setup called TRAID, which shares the same idea as Synology's Hybrid RAID (SHR).

TRAID allows for mixing drives of different capacities, easy storage scale-up, and automatic RAID function—you automatically get something similar to RAID 1 when using two drives, RAID-5 with three or more, etc.—with a slight performance sacrifice.

In any case, the support for TRAID shortens the gap that TerraMaster trails behind Synology considerably in terms of storage management.

Another noteworthy feature is TOS 5 now supports domain/LDAP integration, allowing the server to work as part of a business environment with a domain controller. This feature is a must-have if TerraMaster wants to break into the business environment.

Few useful apps

Apps are where a server shows its power, and in this area, TOS is still much behind DSM.

First, it's the quantity. There are only 55 apps (44 if you take out the Betas—the numbers will change over time). Among these, only a few are useful. The rest are largely irrelevant to general users, and there are no real apps for business users.

For comparison, Synology has over a hundred well-designed apps for all business and home categories.

TerraMaster TRAID
The support for the flexible TRAID helps TerraMaster reduce the gap it trails behind Synology.

That said, I found the following apps significant compared to the previous version of TOS.

  • Snapshot: Similar to Snapshot and Replication of Synology, TerraMaster's Snapshot—available only when you use the BTRFS file system—enables the keeping of versions in shared folders to fight against accidental deletions or alterations. It also supports a replication feature to keep a copy of a shared folder in real-time.
  • Transmission: An app for download, similar to the Download Station of Synology. This app allows users to download BitTorrent files without having to have a PC on, but unfortunately, it has no search function, which is a huge shortcoming, and it doesn't work with other types of downloads, such as FPT or HTTP.
  • Multimedia Server: A server app for streaming content hosted on a TerraMaster server, similar to the Media Station of Synology. TerraMaster doesn't have playback apps on the front end, but Multimedia Server supports standard streaming protocols—you can use third-party streamers with it. On top of that, the server also has a beta version of Plex and Emby—two popular streaming platforms.
  • TerraSync: Including server and Client apps, TerraSync is a copy of Synology Drive that allows syncing and baking data of multiple clients.
TerraMaster F2 223 Snapshot and Remote Access
With TOS 5, TerraMaster servers now have Snapshot, and its remote access—similar to Synology's QuickConnect—remains the same as in previous versions.

None has the same level of in-depth customization for functionality as the Synology counterparts. On top of that, some apps are impossible to use.

For example, the VirtualBox app, supposedly a virtual machine manager, doesn't work at all.

The way the software works, there's hope that things will get better in future updates and releases.

Unfortunately, the particular case of the T6-423 server is primarily negative. Let's start with its hardware specifications.

TerraMaster T6-423 vs. F2-223: Hardware specifications

Similar to the lesser F2-223, the T6-423 is Multi-Gig ready. It has a better CPU but shares the same RAM configuration. In the end, the extra drive bays are its most significant edge over the older cousin.

TerraMaster T6-423TerraMaster F2 223 2 Bay NAS Server out of the box
TerraMaster T6-423TerraMaster F2-223
CPUIntelCeleron N5105/5095
Quad-core 2.0 GHz
(Max burst up to 2.9 GHz)
Intel Celeron N4505
Dual-core 2.0 GHz
(Max burst up to 2.9 GHz)
Hardware encryption engineYesYes
 (Upgradeable to 32GB via one slot)
 (Upgradeable to 32GB via two slots)
Compatible drive type6 x 3.5" or 2.5" 
(drives not included)
2 x 3.5" or 2.5" 
(drives not included)
Hot-swappable driveYesYes
NVMe support2x M.2 slotsNo
USB ports2 x USB 3.2 Gen 2 (10Gbps)2 x USB 3.2 Gen 2 (10Gbps)
Dimensions8.90 x 5.12 x 5.58 in
(226 x 130 x 218mm)
8.93 x 4.68 x 5.23 in 
(227 x 119 x 133 m)
Weight8.6 lbs (3.9 kg)5.2 lbs (2.4 kg)
Network ports2 x 2.5GbE
2 x 2.5GbE
Wake on LAN/WANYesYes
Scheduled power on/offYesYes
AC Input100V to 240V AC100V to 240V AC
Power consumption
(per 24 hours)
≈ 770 Wh
(measured with 6 hard drives)
≈ 490 Wh
(measured with two hard drives)
Maximum storage capacity120TB (2 x 20TB drives)40TB (2 x 20TB drives)
 Maximum local user accounts20482048
Maximum share folders512512
Supported RAID type
Suggested retail price (disk-less)$699.99$299.99
Warranty2 years2 years
Hardware specifications: TerraMaster T6-423 vs. F2-223

The odd physical shape, terrible drive bay design

Out of the box, the T6-423 looks rather odd. The server seems to be an internal part instead of a complete product.

By default, it's designed to stay in a vertical position, but you can also place it horizontally—there are even included rubber feet that you can attach to the new "underside" in this case.

A side of the TerraMaster T6-423. Note how it looks like a cover is missing.
A side of the TerraMaster T6-423. Note how it looks like the cover is missing.

But no matter which you use, other than the front, where the drive bays are, the rest of the server seems unfinished. It's like the product managers originally intended to put the whole thing in a case and then change their minds.

And the drive bay themselves are problematic. Each bay comes with a tray to hold a SATA internal drive. Unlike the case of the F2-223 or F2-221, where you can install drives tool-free, you have to use a screwdriver to mount a drive on the T6-423's stray.

The server includes two sets of screws for the desktop (3.5-inch) drives and the other for smaller laptop (2.5-inch) ones. And that's where things go sideways.

For one, the included screwdriver's tip is too large for the screws. You can't use it. It's quite ridiculous. And secondly, with six drive bays, installing the drives—you have to fumble with four little screws for each—can be tedious and time-consuming.

TerraMaster T6 423 NAS Server 1 9TerraMaster T6 423 NAS Server 1 8
You must use little screws to install the drives, but the TerraMaster T6-423's included screwdriver won't work with its screws.

And turning these drives into accessible storage proved to be a big problem in my trial.

Super buggy Storage Manager

As a storage device, there's nothing more important in a NAS server than the Storage Manager, an app that handles internal disks.

And for a 6-bay server with multiple RAID options, the T6-423 has the worst Storage Manager I've used. There are so many things not right about it, little and small.

For example, the only way to make the server work immediately is to put all available drives into a single storage pool during the initial setup process.

But with a server that can handle these many internal drives, you'd want to use multiple storage options, such as a RAID 0 and a RAID 5. And that's exactly what I wanted to try out, and I had the most challenging time with it.

I started with six 20TB IronWolf Pro hard drives with the server. As the server took more than a day to finish syncing two of them into a RAID 1, I opted for 2TB drives for the testing to save time. Still, specific RAID configurations, including TerraMaster's flexible TRAID, required hours to finish syncing.

TerraMaster T6 423 Control PanelTerraMaster T6 423 Storage
The TerraMaster T6-423's Control Panel and its buggy Storage Manager. It takes a long time to complete a redundancy-enabled RAID to complete syncing, by the way. This TRAID of less than 6TB of storage took over six hours to finish.

Initially, building a second storage pool using available drives seemed impossible. The process would start, and then nothing happened.

At first, I thought the server only worked with a single storage pool. So to experience the server with a different RAID configuration, I had to re-set it up from scratch. It was very frustrating.

Later on, I found out that it was because of the lag. The server's Storage Manager took five to 10 minutes, or even longer, to show a new Storage Pool in the system—the larger the hard drives, the longer the lag.

So, I decided to use a couple of SSDs for the boot volume. Now things are better, but the lag was still there.

And then, when a new storage pool was successfully created, it was also named "Storage Pool 1", so I'd have two or even three "Storage Pool 1" in the system, making it confusing to know which is which.

But after I restarted the server, the system showed them correctly as "Storage Pool 1," "Storage Pool 2", etc.

Long story short, the server's Storage Manager could use some whale-size improvements. The way it works right now, it's impossible for any advanced user to trust it. I didn't. I was scared of its finickiness.

Hopefully, that will happen via OS updates.

TerraMaster T6-423: Extra photos

TerraMaster T6 423 NAS Server 1 13TerraMaster T6 423 NAS Server 1 12
The front and back of the TerraMaster T6-423 NAS server.

TerraMaster T6 423 NAS Server
The internal drive bays of the TerraMaster T6-423 are a little too close to each other.

TerraMaster T6 423 NAS Server 1 4
You can use the server in the horizontal position, too.

TerraMaster T6 423 NAS Server 1 14
The server looks unfinished from the other side, too.

TerraMaster T6 423 M.2 NVMe Slots
You need to open the side of the server to get to its two M.2 NVMe slots and a RAM slot.

Other issues

Besides the Storage Manager mentioned above, the T6-423 had other little reliability issues in my trial. Here is a short list:

  • Changes not consistently applied: The server often doesn't apply common settings. For example, I set the time zone to Pacific and applied the changes. After the server failed to execute some scheduled tasks, I discovered that it was still using its default Hong Kong time zone. Turned out I needed a restart for the new zone to be in effect.
  • Case-sensitive username: The server uses Linux's default case sensitivity for the username, making it unfriendly to general users who tend not to remember this. Many other NAS servers don't do this.
  • Restart often required: Generally, you'd have to restart to ensure that the changes you've made to the server are applied. With the T6-423, what you see on its interface is not what you get most of the time until after a restart.

It's important to note that the issues with the server themselves are not consistent. They might happen, or they might not. But one thing is for sure, something will not happen the intended way.

In other words, during my trial, even the server's bugginess is buggy. That might sound odd, but there's no other way to put it. There's little consistency with the hardware.

Overall, the T6-423 has a big issue with reliability. During my week-long trial, I always felt unsure, worrying that some functions might stop working out of nowhere. And some did, until a restart.

TerraMaster T6-423: Multi-Gig-class performance

With two 2.5GbE ports, the T6-423 did well in my performance tests. I tested it via standard RAIDs, including RAID 0 and RAID 1 (both with two drives), using hard drives and SSDs, and the server delivered fast sustained speeds, though not speedier than the F2-223.

TerraMaster T6 423 Read PerformanceTerraMaster T6 423 Write Performance
The TerraMaster T6-423's performance with standard RAIDs using hard drives and SSDs as storage

It's worth noting, though, that the server's TRAID performance (not shown on the charts) is significantly slower than RAID 1 (2 drives) or RAID 5 (4 drives). So if you want the best performance, it's a good idea to use a standard RAID.

Unlike the case of the F2-223, the T6-423 ran a bit noisy in my trial. Its fans—even when put in quiet mode—produce enough noise to be a nuisance in a quiet room.

TerraMaster T6-423 6-Bay NAS Server's Rating

6 out of 10
TerraMaster T6 423 NAS Server 1 11
7 out of 10
6 out of 10
Ease of Use
4 out of 10
7 out of 10


Two built-in 2.5Gbps Multi-Gig ports; fast performance

TOS 5 includes domain/LDAP integration, robust interface, TRAID, Snapshot, and more

Six drive bays with multiple RAID options


Extremely buggy Storage Manager; lots of little issues; unmatured OS and apps

Impractical, bulky design, hard-to-reach NVMe/RAM slots

No 10GbE upgrade or IP camera support


The TerraMaster T6-423 is a missed opportunity. The server could be a much better network storage hardware if it improved based on the F2-223. Instead, the completely new design makes it impractical and annoying to use.

And the currently buggy operating system, lackluster apps, and other little oddities don't help. The server fails to live up to its intended goal of being an advanced server, making it a bad deal even for the relatively low $700 price tag.

Use it as a bare-basic NAS device with fast throughout, or opt for the much more refined Synology DS1621+ instead. The latter will save you from a ton of headaches down the line.

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8 thoughts on “TerraMaster T6-423 6-bay NAS Review: Impractical Design Meets Buggy Hardware”

  1. One major advantage of these TerraMaster systems is that if you don’t like their software (which in fairness they seem to be working on), you can easily update to whatever NAS software flavour you want, simply using a small USB drive.

    I view that as a significant feature, having previously used Qnap.

    Also, the specifications on TerraMaster’s webpage show 2 memory slots, so you could populate with a 2 x 16Gb of Ram, and a couple of NVME in the M2 for cache.

    Hardware seems quite good for the price – software is replaceable 🙂

    • Just found another review on ITPro that says “the second SODIMM slot is underneath the motherboard, which is connected to the backplane with a single-edge connector”.

  2. T6-423 does have 2x NVME slots. Look again.
    Also about the screws, how often do you remove/put in a new HDD? I dont mnid it too much, its rarely a thing in my opinion.

    • You’re correct, Andre. I was too consumed by the server’s issues with its drives that I overlooked these slots. Thanks for pointing that out!

      And no, most people don’t need to have to handle the drives often, but in my case, it was a pain considering the number of tests I wanted to do. And tool-free installation is generally always a bonus. That’s the case with the F series.

  3. The disconnect between the GUI and actual settings is very worrying. For a little extra money, get a lot more reliability with Synology or even QNAP in second place. Especially if forking out for 20Tb Drives, be a shame to stuff them into this t6-423

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