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TERRAMASTER

TERRAMASTER D4-320 External Hard Drive Enclosure 4-Bay (Diskless)

Based on 409 reviews
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$189.99
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At a glance

Condition
New
Model
D4-320
Storage
88 TB
Dimensions
8.74"L x 7.05"W x 6.06"H
Weight
1.3 lb
Color
Black
Hardware Interface
SATA 6.0 Gb/s, USB 3.2 Gen 2
Warranty
2 Years
Works with
Windows, Mac, Linux

Features 5

  • High-Speed Data Transmission: The D4-320 hard drive enclosure (a DAS, NOT a NAS) utilizes the USB 3.2 Gen2 protocol, achieving high-speed data transmission of up to 10Gbps. When equipped with four hard drives, the actual read/write speed can reach up to 1,016 MB/s (combined read/write with four SATA III HDDs of 8TB each). With just one SSD installed, the read speed effortlessly reaches 510 MB/s (SATA III 1TB SSD). The D4-320 supports a single HDD up to 30TB, with a total capacity of 120TB, and is compatible with various hard drives, including 3.5-inch SATA hard drives, 2.5-inch SATA hard drives, and 2.5-inch SATA SSDs
  • Plug-and-Play Compatibility: The D4-320 USB storage supports 4 individual disks (NO RAID function), and is plug-and-play, eliminating the need for drivers. It is highly compatible with MAC, Windows, and Linux operating systems. The USB Type-C interface supports various computer interfaces, including USB 3.0, USB 3.1, USB 3.2, Thunderbolt 3, and Thunderbolt 4
  • Hot Swappable Convenience: The D4-320 HDD enclosure supports hot swapping, allowing users to replace hard disks without powering off the device. This feature enhances convenience and efficiency in data transfer processes
  • Tool-Free Hard Drive Management: Featuring a tool-free hard drive tray design, the D4-320 external HDD enclosure enables easy installation and removal of hard drives without requiring additional tools. Furthermore, the D4-320 incorporates TerraMaster's unique Push-lock design, automatically securing the hard drive tray upon insertion, preventing the hard drive from falling out or disconnecting

Description

TerraMaster’s focus has been on digital storage products. In line with the evolving technological landscape, TerraMaster has developed a distinctive product line, which includes both direct and network attached storage devices. At present, TerraMaster sells its products in more than 40 countries, which are widely used in education, finance, government, supermarkets, clinics, scientific research, law firms, film production, home, and other fields. New Upgrade, Refreshed Experience: As an upgrade to the classic D4-300, the D4-320 hard drive enclosure offers several revolutionary changes while maintaining affordability. Its new design concept offers a stylish and minimalist appearance that is more aesthetically pleasing, while its underlying technology offers a qualitative leap in terms of performance, allowing users to access outstanding functionality. Enhanced Speed and Performance: Utilizing USB 3.2 Gen2 protocol, the D4-320 USB storage achieves lightning-fast data transfer speeds of up to 10 Gbps, doubling the speed of its predecessor (D4-300). Whether handling multiple hard drives concurrently or a single drive, the D4-320 consistently delivers exceptional performance, reaching read/write speeds of up to 1,016 MB/s (combined read/write with SATA III HDDs x 4). Even with just one SSD installed, the read speed effortlessly reaches 510 MB/s (SATA III 1TB SSD). Thus, whether using multiple hard drives operating in parallel or ensuring the efficient operation of a single hard drive, the D4-320 demonstrates exceptional performance. Flexible and Compatible Connectivity: The D4-320 direct attached storage boasts strong interface compatibility with its USB Type-C interface, providing seamless connections to various computer interfaces, including USB 3.0, USB 3.1, USB 3.2, Thunderbolt 3, and Thunderbolt 4. Its hot-swappable support and driverless, plug-and-play functionality make it a versatile and user-friendly storage solution, compatible with different operating systems and devices. Convenient and Efficient Hard Drive Management: The D4-320 HDD enclosure introduces a revolutionary tool-free hard drive bracket with a Push-lock design, allowing quick and secure installation without the need for tools. This innovative design ensures stable data transmission, greatly enhancing the efficiency of hard drive replacement. Swapping hard drives becomes a seamless process, providing added convenience for users who frequently switch drives. Additionally, the D4-320 is exceptionally quiet during its operation, thanks to its specialized sound-absorbing panels and vibration damping, which reduce noise levels by up to 50% compared to the previous generation, dropping below 21 dB(A) in standby mode for a remarkably quiet user environment. Versatile Storage Expansion: With support for up to four hard drives, each with a maximum capacity of 30TB, the D4-320 offers a powerful storage expansion of up to 120TB. Based on careful adaptation and optimization by the professional team at TerraMaster, the D4-320 offers seamless connection to the USB interface of TerraMaster NAS. Leveraging the powerful TOS system developed by TerraMaster, users can easily create arrays and storage pools on the D4-320, effectively expanding the storage space of their NAS to meet growing demands for data. This feature is only applicable to TerraMaster NAS devices running TOS 5.1 or above. Based on this innovative feature, the D4-320 provides users with a more flexible and diverse storage expansion solution. Note: Some mini PCs may have weaker USB signal output, which can cause random interruptions during file read/write operations during data transmission. When this occurs, it is recommended to 1) use the rear USB ports of the computer, as they typically provide a more stable signal; 2) test the device on another known-good computer to rule out hardware issues on the original PC; and 3) use a 10Gbps USB-A/USB-C hub or splitter with a short 0.3m–0.5m cable to reduce signal loss. TERRAMASTER D4-320 TERRAMASTER D6-320 TERRAMASTER D5 Hybrid TERRAMASTER D8 Hybrid

Specs 22

Hardware Interface SATA 6.0 Gb/s, USB 3.2 Gen 2
Brand TERRAMASTER
Color Black
Product Dimensions 8.74"L x 7.05"W x 6.06"H
Hardware Platform Windows, Mac, Linux
Memory Storage Capacity 88 TB
Hard Disk Form Factor 3.5 inches
Supported Devices Quantity 4

Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Sunday, Nov 15

Yes, absolutely! This item's return window has been extended for the holiday season: FREE refund/replacement until Jan 31, 2027.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Similar Products

Top Amazon Reviews

Just what I needed
Model: D4-320
I upgraded my computer and went with a smaller case that couldn't accomodate all of my drives so I went looking for a DAS (didn't want a NAS because my network is only 1gbit and didn't want to be limited to those speeds). This was exactly what I was looking for. I have 3 Samsung 870 Evo SSD's as well as a Seagate EXOS 24TB hard drive in this and they all work as if they were plugged directly into the motherboard. I didn't use any extra software or do any type of RAID or anything so I can't comment on anything other than just plugging drives in and using them as all individual drives. Due to my placement of this DAS I had to buy a separate 10ft USB C cable which gave me the same exact speeds as the included cable (if you go this route just double check that you're getting the correct cable), that's also the same speeds I was getting when they were plugged in via SATA. I originally thought I was going to need some kind of 2.5" to 3.5" adapter to be able to use the SSD's but then I noticed the sleds in this have screw holes to be able to screw in 2.5" drives and it has screws included so nothing extra was needed. The sleds have these plastic pieces on each side (I think they're used for holding the 3.5" drives but I didn't pay enough attention), which needed to be removed to be able to screw in the 2.5" drives. Overall installation was extremely simple and I think anyone who knows that they need something like this can probably figure out how to put the drives in (I don't recall seeing any kind of visual instructions but I also didn't look very hard). You put the drive in the sled, and then slide it in. It's that simple. And the overall build quality is totally fine. Nothing crazy but it's nice and firm plastic, perfectly acceptible and what I was expecting. The DAS itself is quiet, but the sound of my hard drive reading/writing is a lot more noticable in this than it was when I had it in my old PC case which I found odd since the old case was a lot closer to me than this DAS is. This isn't really that big of a deal to me but could be for other people. The fan is so quiet that even if I put my ear right up next to it I can't hear it over the ambient noise in my house. Not sure what else I can say as I've only had it for a day now and it's done exactly what I needed it to do. If something bad happens I'll update this review, but as of now it's perfect. ... show more
Reviewed in the United States on March 21, 2026 by Zatch
Fatal Flaw to what could be the solution for photographers
Model: D4-320
Update 3/26/2026 Sorry for the false alarm below. The issue was with the power supply, not with the device. The power supply had the same brand name and appeared virtually identical, so I just plugged the new one into the same power supply, but then out of abundance of caution I glanced at the fine print on the old power supply and realized it says 72 watts (W) of output, and then I glanced at the new one, but it said 120 W of output. A huge difference, clearly. After carefully untangling the cables needed to take out the old power supply from my double-layered set of Bluetti and CyberPower battery backups, and put in the new power supply, the 6-bay model does work flawlessly, and has enough power to spin up all four drives at once. Just a note of caution, since 72 W of power is NOT enough for four drives, this means each drive probably needs at least 20 W apiece to spin up (for Exos enterprise drives). Thus, six drives would likely need at least 120 W total, meaning that the new power supply may or may not be enough power to actually spin of six drives. When I do ever sometime install six drives at once, I might run into the same issue of not having enough power to spin all the bays up that the machine is rated for, just like I experienced with the 4-bay version not having enough power to spin up all of its bays. But for now, when I am only using my four drives in this 6-bay unit, and with its correct PSU included in the box, rather than the prior one, it does have enough power to spin up the four drives with two of the bays empty. It's kind of an extreme cost cutting measure that the PSU included saves like 15 cents of cost by only putting out 72 W for one model and only 120 W for another model, but I respect the right of a company to just include the bare minimum to make its product work. Although the prior 4-bay model did NOT work with 4 drives loaded in it, and it still awaits to be seen whether the 6-bay model will work with a full load of 6 drives in it as well. Other than this power issue, this unit has worked flawlessly and perfectly for over a year on my MacBook Pro M4 Max, and hopefully it will keep doing the same on my new MacBook Pro M5 Max. Update 3/26/2026 For the past year, I have been stuck with hot swapping the 4th drive after powering up this model just so that it can boot, as it powers off from a voltage deficiency over and over in an infinite loop when 4 drives are loaded. So today, in the spring sale, my package arrived with the new 6-bay version. Obviously, with 6 bays, it should have more voltage to be able to spin up just by 4 existing drives, right? Wrong. I am attaching a video showing the infinite loop STILL happening of trying to spin up just four drives, then failing, which happens on the 6-bay model, just the same as on the 4-bay model. DO NOT BUY THIS PRODUCT. IT CANNOT LOAD MORE THAN 3 PHYSICAL HARD DRIVES AT A TIME, EVEN THOUGH IT CLAIMS TO SUPPORT SIX. The package has been opened and all the screws taken out, but hopefully I can still do a return and go back to my 4-bay model, and keep on living with this terrible situation of loading in the 4th drive after waiting for the first 3 to spin up. I live in daily terror that at some point my timing will be off, and my computer will see the missing drive as a corrupted software RAID array, instead of getting the timing just right so that my computer thinks there is just a small delay in loading up the fourth drive from the enclosure, instead of seeing it as a missing drive/corrupted RAID. Original Update: when used with 4 seagate 28 TB drives, it cannot spin up because inadequate voltage. One drive has to be slid out partway when turning on, then slid back in after the first 3 spinup. Otherwise, still works great. Only this drive so far can't spin up with 4 drives inside. Other drives don't need so much voltage, apparently. -- I generate over 20 TB of media a year as a photographer, and I now use software raid only after way too many unrecoverable hardware raid failures. And I also use backups on additional DAS devices, never trusting just raid alone for safety. But I have always been frustrated that good enclosures are close to $300 or even $1000, just to provide a decent 1000 MB/sec of combined speed from multiple drives. Lots of DAS devices are available, but until this one, it was always close to $300 or far more just to get true drive speed like 250 MB/sec for one drive times four = 1000 MB/sec total. Why should I pay the price of an entire new PC just to provide a SATA connection and power cable to my drives that doesn't bottleneck my speed when accessing more than one drive at once with RAID? Finally this one is available for half the cost, and it really works. I've bought four and will buy more. ... show more
Reviewed in the United States on August 30, 2024 by Joseph
Easy to install, works perfectly.
Model: D4-320
Mounts very quickly and easy, transfer speeds are great the way they are supposed to be. So far so good and I have my backups running along with Immich. Great fan to keep drives cool and very quiet, can't even hear it.
Reviewed in the United States on September 22, 2026 by JFLY
Not good for Software RAID on Mac
Model: D4-320
Let me preface by saying that this product might work just fine for someone using Windows or Linux, but my experience with MacOS left me sore. I bought this enclosure hoping to run SoftRaid on my old M1 Mac Mini serving up a half dozen RAID 5 volumes for my family to use for Time Machine backups. I paired it with four 4TB Western Digital Red Plus drives which were listed as "Recommended" on the Terramaster web site. SoftRaid identified a disk is faulty, I replaced it, a few days later it reported two bad disks one of which was the one I had just replaced. I contacted support from SoftRaid who looked at the data and said the Mac USB drivers sometimes can't handle the load and I would be happier with a Thunderbolt enclosure. Which I eventually switched to. That being said, it has a plasitic enclosure and a detached floor brick DC power supply. I suspect it would be fine for a PC or Linux environment, but for software RAID on a Mac, I would avoid it. ... show more
Reviewed in the United States on January 15, 2026 by DuoArtDude
BEWARE: These may not be able to power up all four drives at once
Model: D4-320
UPDATE (Still be aware of your drives' power draw): Terramaster sent me an upgraded power supply (90w vs 72w) to see if it would power up the EXOS drives more reliably. The larger power supply does handle the peak power draw on these drives better. My Kill-A-Watt measures peak power draw when all 4 drives are spinning up at just under 150w, which is too much for the included 72w power supply. Most drives are not going to need this much power, and the unit will work fine for most consumer drives, and most smaller capacity drives. Check the peak power draw in your drives' user manual. This is typically not the same as the numbers on the spec sheets, at least for EXOS drives. For example, the EXOS drives peak at around 35 watts during spin-up, while the spec sheets only discuss the running power at around 10 watts. If you have issues with your drives failing to spin up, contact Terramaster and request the 90w unit, or even better, contact them before you purchase and see if they can send you one to begin with. Other than this issue, the unit is great. It is quiet, easy to install the drives, and seems to just work. That, and the fact that TM volunteered (I didn't ask) to send out a larger power supply, is why I'm bumping this to 4 stars instead of 3. I have a feeling that this unit will just work for most people. INITIAL REVIEW: BEWARE: The unit does not have enough power to spin up 4 drives simultaneously, at least with the Seagate Exos drives I put in. You may need to pull a drive, let it spin up the 3 remaining drives, then insert the last drive hot. This is the only way I've been able to get it to work with 4 drives. Apparently some manufacturers spin up the drives in sequence, rather than simultaneously in order to avoid this problem. This is a HUGE problem for a device that advertises support for 4 drives. Requiring physical interaction like pulling a drive at every power up is problematic. I haven't yet tested whether this will affect the usage post power-up. If, for example, the drives spin down, will it even be able to spin them back up when data is being accessed? I've emailed customer support about this, and will update the review when / if I hear back. ... show more
Reviewed in the United States on July 20, 2025 by Amazon Customer
Great 4-disk enclosure
Model: D4-320
The self-noise is very quiet although there isn’t much dampening for hard drive noise so the actual drives may be very audible. The fans work great and keep my drives consistently below 40C. The case feels a bit cheap because of all the plastic but I kind of prefer this since it’s so light weight. Despite the plastic case, it feels really solid. The case should hold up for years. The lights on the front are really helpful to confirm disk activity. I only have two complaints: how the drives show up in windows and the quality of the USB-C connector. Each drive shows up individually which is great for software RAID, but ejecting the drives means each one has to be removed from windows separately. I wish there was a way to eject them all as one device before I disconnect the enclosure. The USB-C connector also could be stronger. If something accidentally bumps into the cable while it’s in, it can disconnect from the host even if the cable looks like it should still be connected. Despite these concerns, I’m very happy with this enclosure. ... show more
Reviewed in the United States on April 3, 2026 by Zack S
Fantastic DAS - But Throw Away the Stock Cable Immediately (1.5-Year Review)
Model: D4-320
I have been running the TerraMaster D4-320 for a year and a half now, and it has performed flawlessly. My setup consists of four 22TB Western Digital Ultrastar DC HC570 enterprise drives configured in a software RAID10 array on a Linux NAS. It has been so reliable and stable that I just ordered the 2-bay version, the D2-320, to expand my storage even further. However, looking at the negative reviews complaining about random drive disconnects, frozen transfers, and data corruption, I am confident that a huge percentage of these bad experiences come down to one single, easily avoided issue: the factory USB cable included in the box. These 320-series enclosures operate on a high-speed 10 Gbps (USB 3.2 Gen 2) interface. When you are multiplexing data from up to four separate hard drives down a single USB line, the connection is incredibly sensitive to signal degradation. The stock 1-meter cable included with the unit is simply too thin and too long for this specific high-bandwidth hardware specification. Under heavy or sustained write loads, the signal degrades over that distance, causing the data packets to drop. The host operating system loses track of the connection, panics, and resets the drive link - which looks to the user like a random disconnect or a corrupted array. The Fix is Simple: Do not use the factory cable. Instead, replace it immediately with a short, thick, heavily shielded USB cable rated explicitly for 10 Gbps or USB 3.2 Gen 2. I personally use a high-quality 0.5-meter (1.6 feet) heavily shielded cable (the kind typically bundled with external NVMe SSD enclosures). Keeping the cable short and thick does two vital things: 1. Eliminates Signal Loss: Shorter distances mean the high-frequency data signals arrive clean and error-free without the enclosure needing to constantly re-transmit corrupted data. 2. Reduces Electrical Resistance: Thicker copper wires ensure that when the enclosure spikes in power usage during heavy metadata operations, the voltage remains completely stable across the connection. If you treat the stock cable as temporary packaging and swap it out for a heavy-duty, short 0.5m cable from day one, this enclosure is an absolute tank. Highly recommended, just budget an extra ten dollars for a proper data cable! ... show more
Reviewed in the United States on May 29, 2026 by Kevin
Excellent and worth the extra coins over the competition. Self-hosting game changer for me.
Model: D4-320
Better than others by far. This is about the fourth or fifth one of these enclosure things I've bought and this one is the best by far. Build quality is excellent and made of thick plastic (quieter than aluminum). Stay away from the Mediasonic brand ones if you are using it for a server - I've gifted away two of those because the power button always had to be pressed after power loss and the usb controller was shared by all the drives (it also was weird with device naming). I'm using the TerraMaster with a Raspberry Pi 5 8GB running OMV 8, with one 8TB CMR hdd and two 6TB SMR hdd. It has a USB controller for each disk slot and I was pulling full read write speeds from the disks simultaneously. I also didn't have any disk sleeping issues (after disabling SMART monitoring and using HD-idle instead of OMV's built-in stuff). The power button is last state; it powers back ON after power loss if it was ON before the power loss. I found the trays easy to install my disks into and the latching click is very satisfying. The fan is quiet enough for my application. I used it in Unraid as well for some testing and everything looked fine on that too - including the device naming. I was copying over 400MB/s to it using a btrfs raid0 array of SMR disks over plain old usb 3.0. ... show more
Reviewed in the United States on March 8, 2026 by kompewterz
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