yottamaster.com Arvostelua 

The 2-bay Yottamaster DAS storage (P/N: DR2RC3-35) was bought on Aliexpress in June 2026 for my notebook Asus Vivobook with Windows 11 Pro, 25H2. Two new HDDs I intended to use - 6 TB Seagate IronWolf, P/N: ST6000VN006.

AliExpress delivered the ordered DAS storage without delays, in good condition – it was well done without any objections. Delivery took 12 days including customs clearance – for my opinion it is very good. The package includes DAS itself, a set of cables, gender changer USB Type C receptacle to USB Type-A plug, screwdriver for device assembling, set of screws, power supply 12 VDC 4A and manual. No serial number on the DAS device, but looks good.

Storage was assembled, connected to the notebook by USB cable – without problems. Problems started after.
After switch on DAS unit – computer shows 2 unallocated HDDs in the Disk Management System Tool. After switching the RAID switches on the back side to set up RAID 1 – nothing changes. System shows 2 unallocated HDDs regardless of any position of these switches. Switching off, switching on together with holding down SET button – does not help. Nothing changes – only 2 unallocated HDDs. No RAID. Both HDDs have the same serial number.

I wrote the enquiry to support with the problem description. Received the answer that in couple of working days somebody from the technical support team will contact me. Today 4 weeks have passed – I am still waiting. Reminder letters do not helped, they forgot about me.

So, I decided to arrange RAID by Storage Spaces functionality in Windows OS. I created a new pool, but something non-correct happened and computer did not see a new disk in the File Explorer. After very long interaction with PowerShell panel, I revealed that:
1. HDD disks are alive
2. Storage pool created correctly and healthy
3. Mirror created correctly and healthy
4. Partition is alive
5. Partition has RAW file system despite that I chose NTFS (!)

After that using manual commands, I formatted disks and gave a name.

Hurray! Now computer shows a new disk with volume of 5,4 TB:
1. FriendlyName D
2. Resiliency Mirror
3. OperationalStatus OK
4. HealthStatus Healthy
5. Size 5.4 TB

But it was not to be! I tried to write something to the new disk - it goes. But after few files transferred to the DAS – it totally drops during writing procedure and not seen in the File Explorer. After being switched off \ on – DAS again in working condition. But after new attempt to write to DAS – it drops again.
I am wondering what the Yottamaster Technical Support is doing now?

CONCLUSION
1. May be the problem originates from interaction between these Seagate HDDs and DAS Controller – no possibility now to check it. But Seagate is one of the biggest HDD manufacturers.
2. I cannot recommend to anyone to buy and use this Yottamaster DAS.
3. I have only one way out – to use another DAS because the DR2RC3-35 what I received is not operational.
Hope that this information is useful.

I bought this enclosure to expand my Unraid server, and after a year of "okay" performance, it has completely failed in a way that caused significant data loss.

The JMicron bridge chip inside this unit is fundamentally flawed. It has an aggressive, hardcoded "Green" sleep timer that cannot be disabled via software. Even worse, it has a major issue with SCSI-to-ATA Translation (SAT). When used in a Linux or Unraid environment, the controller frequently crashes during heavy I/O, reporting a limit=0 capacity to the OS and triggering thousands of Command Timeouts (SMART ID 188).

The enclosure enters a "disconnect/reconnect" loop where the power light stays blue, but the activity light flashes red every second. During this state, the bridge chip "hangs," making the drive appear as 0 bytes to the system. This corrupted my file system's metadata and forced a total drive failure.

Even with the dedicated power supply plugged directly into a wall outlet, the unit struggles with the "inrush current" required to spin up 3.5" drives. This voltage sag causes the bridge chip to reset, disconnecting your drives in the middle of write operations.

If you value your data, STAY AWAY. This is fine for a temporary USB "thumb drive" style backup, but it is NOT fit for 24/7 server use, parity arrays, or any setup where disk stability is required. The JMicron controller is a ticking time bomb for your data.

EDIT: Have not received a response from support after nearly a month.