TerraMaster Forum

March 18, 2025 – TerraMaster, a trusted leader in innovative storage solutions, proudly introduces the D4-320U, a compact 1U 4-bay direct-attached storage (DAS) enclosure designed for small offices, home users, and IT environments. Combining a space-saving rackmount design, massive 88TB storage capacity, and lightning-fast 10Gbps USB 3.2 Gen2 performance, the D4-320U delivers unmatched versatility and efficiency for modern data demands.



D4-320U Key Features

Compact Design for Seamless Deployment
The D4-320U redefines convenience with its miniaturized 1U rackmount form factor. Measuring just 241mm (9.49 inches) in depth, 50% shorter than traditional chassis and weighing 3.2kg, this sleek enclosure fits effortlessly into standard server racks without the need for rails, simplifying installation. Its space-efficient design maximizes room utilization in data centers, storage closets, stairwells, or offices, making it an ideal choice for small businesses and SOHO users seeking centralized storage solutions.

Massive 88TB Storage Capacity
With support for up to four drives, the D4-320U offers a staggering maximum capacity of 88TB (using 22TB drives, with larger capacities pending compatibility verification). Operating in single-disk mode by default, users can leverage third-party software RAID tools to create arrays, catering to extensive storage needs from media libraries to enterprise backups.

High-Speed Data Transfer at 10Gbps
Equipped with the USB 3.2 Gen2 protocol, the D4-320U achieves a blazing 10Gbps bandwidth. When paired with four 8TB WD Red HDDs, it delivers read/write speeds of up to 1,016MB/s. Even with a single 1TB WD Red SSD, users can enjoy read speeds of 510MB/s. This exceptional performance ensures rapid data access and transfer, perfect for professionals and enthusiasts alike.



Expandable NAS Integration
Optimized for TerraMaster NAS devices running TOS 5.1 or higher, the D4-320U connects via USB to expand storage pools and create arrays through the robust TOS system. This feature makes it a powerful companion for users looking to scale their NAS capacity with ease.



Plug-and-Play Simplicity
The D4-320U offers true driver-free, plug-and-play functionality, seamlessly supporting macOS, Windows, Linux, Ubuntu, TrueNAS, Unraid, and more. Compatible with USB protocols, it connects effortlessly to PCs, TVs, servers, and set-top boxes. Included 0.8m USB A-to-C and C-to-C cables ensure compatibility with USB 3.0, 3.1, 3.2, Thunderbolt 3, and Thunderbolt 4 interfaces for stable, high-speed connectivity.

Robust Safety and Efficiency Features
Power Protection: Advanced safeguards prevent damage from mismatched power inputs, ensuring hardware longevity.
Power Recovery: Smart memory resumes the device’s prior state after power outages—staying off after a normal shutdown or auto-starting post-
disruption—ideal for unattended server or NAS setups.
Intelligent Hibernation: Drives enter sleep mode with the host system, reducing wear and energy use while extending lifespan.
Quiet Cooling: A smart, temperature-controlled low-noise fan and optimized airflow keep drives cool and quiet, even under full load.



Automated Backups Made Easy
With TerraMaster’s TPC Backupper for Windows (8/8.1/10/11), users can schedule incremental or differential backups of folders and partitions to the D4-320U or a TerraMaster NAS.

More TerraMaster Storage Devices
The D5-310 5bay RAID storage device was released at the same time, forming a "enterprise + personal" dual product line layout with the D4-320U. Users can now purchase new products throughTerraMaster Official Mall and authorized channels, and enjoy a 2-year warranty service.

For more information, please visit: https://www.terra-master.com/us/product ... -320u.html.

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About TerraMaster
TerraMaster is a professional brand that focuses on providing innovative storage products, including network attached storage and direct attached storage that has become increasingly popular in over 40 countries and regions. The brand has been developing storage technology for 10 years, addressing the needs of customers such as home users, small/medium businesses, and enterprises.

Hey guys, this is great.

Can you please let me know which chipset is the USB based on? I need to know this information before making a buying decision.

Or maybe just confirm if they are like this:

USB 3.2 Gen 2 hub: Realtek RTS5423

Per-bay SATA–USB bridge: ASMedia ASM235CM, with UASP.

Thanks!

lrm wrote: ↑23 Aug 2025, 01:50

It's an all RealTek solution, based on this image from a third-party review:

can i ask would this handle seagate barracudas or would they struggle same as the NAS drives do with them?

reason for asking is this would be a really neat solution for me as i am currently using 2x USB enclosures each with 6TB seagate barracudas in but as soon as they are put into the NAS drive bays themselves it causes lots of issues with the NAS drives (i accept they arent on the NAS compatibility list)

using the USB enclosures seem to mitigate the issues and they work perfectly with the USB barrier, would the DAS give the same barrier or would TOS or equivalent software in the DAS have the same issue if they were to be put in the bays of the DAS?

also while im here, are there any plans to offer a D2-320U?

Hello! Could you please elaborate further on the specific application scenarios or work environments in which you would consider deploying a 2-bay rackmount DAS (Direct-Attached Storage) product?

TMjack wrote: ↑29 Aug 2025, 08:47 Hello! Could you please elaborate further on the specific application scenarios or work environments in which you would consider deploying a 2-bay rackmount DAS (Direct-Attached Storage) product?

the exact same reasons you would deploy a 4 bay rackmounted DAS but only cheaper

why do you need 4 bays when 2 bays would be enough, especially given the capacity size of hard drives

you offer 2 bay nas drives aswell as 4 bay nas drives

but to elaborate i use USB drives as a form of backup of the 2bay nas drive, so a 2 bay DAS would fit my use case as the other two bays in a 4 bay DAS would not be populated with hard drives

£300 for a 4 bay DAS or £15 for a single USB enclosure is a big difference

Thank you very much for your thoughtful sharing!