UGREEN DXP2800 - ZFS Errors On New Drives

[rayland]

Note that this is a cross-post from Reddit r/zfs (I would link but am not allowed).  The NAS Compares YouTube channel is what helped me make my decision to purchase a UGREEN (thank you!).

I have a relatively new UGREEN DXP2800. This model has the onboard 32G EMMC storage, 2 NVME slots, and 2 SATA bays.  From a hardware standpoint, I:

• Disabled the EMMC storage and watchdog in BIOS
  
• Populated one of the NVME slots with a 1TB Samsung 990 for the OS
  
• Populated the two SATA bays with 6TB WD Red drives (WD6005FFBX-68CASN0)
  
• Upgraded the single SO-DIMM RAM from 8G to 16G (Crucial DDR5 4800)
  

I installed Rocky Linux 9 for the OS and OpenZFS 2.1.16 (kmod).  I'm not using ZFS for the OS volumes.  The WD Red drives are in a mirror.

I setup this host to be a ZFS replica of my primary storage using Sanoid; it isn't running any workloads outside of being receiver of ZFS snapshots. The datasets are encrypted and not unlocked on this receiving host.

Shortly after starting the data transfers, the pool on the UGREEN system went into a degraded state showing write errors on one of the mirror members.  I replaced the drive that ZFS showed write errors on with another brand new drive WD Red of the same model and issued a `zpool replace ...` to update the pool and resilver.

About an hour into the resilver, ZFS is now saying that the new drive also has errors and is faulted. Seems kinda sus...

I'm going to try flipping the drives to opposite bays to see if the errors follow the drive. I'm also going to try (at a different time) reverting to the original 8G RAM that came with the unit.

Any other thoughts?

[ed]

Thanks for sharing your detailed setup and troubleshooting steps.

Given the errors persist even after replacing the WD Red drive with a new one of the same model, and now the new drive also faults during resilvering, this points toward a potential hardware issue outside the drives themselves.

Your plan to swap the drives to opposite SATA bays is a good next step. If the errors follow the drive, it’s likely a drive problem; if they stay with the bay, it could be the SATA controller or cabling.

Since you upgraded RAM from 8GB to 16GB DDR5 4800, and ZFS is very sensitive to memory issues, reverting temporarily to the original 8GB RAM is also smart. Faulty or incompatible RAM can cause silent data corruption or I/O errors under heavy loads like resilvering.

Other things to check or try:

Ensure the SATA cables and connectors are firmly seated and of good quality.

Check the UGREEN firmware/BIOS for updates that might fix storage stability issues.

Test the drives on another system to confirm they’re healthy.

Look into your power supply—unstable or insufficient power can cause write errors during heavy disk operations.

Review the kernel and ZFS logs carefully for any additional clues.

Try running some SMART self-tests on the drives to confirm drive health.

Since you disabled the onboard eMMC and watchdog, ensure that these changes aren’t impacting stability unexpectedly.

Overall, my guess is either a faulty SATA port/controller on the NAS or possible memory compatibility/stability issues after your RAM upgrade.

[rayland]

Sooo.... Here I am coming up on 2 weeks later... I cleared the errors to try and start the troubleshooting through juggling process aaaaaand - the errors never came back.

The system does pretty heave writes every day - which is what it was doing when the errors originally cropped up - so I dunno.

As the BOFH would say - solar flares.