Hello everyone
I am experiencing a recurring issue with my UGREEN NAS: the SSD cache is regularly reported as “degraded,” even though both SSDs appear to be working perfectly according to the system and SMART tests.
My setup:
– 4 × 10.9 TB HDDs in Storage Pool 1
– 2 × Samsung 990 PRO 2 TB SSDs installed in M.2 slots 1 and 2
– SSD firmware: 5B2QJXD7 (up to date)
Since the SSD cache kept being marked as degraded, I created a Volume 2 as general storage for testing purposes. However, even in this configuration, the NAS suddenly reports the SSD storage as degraded after some time.
SSD temperatures remain stable between 40 °C and 42 °C.
NAS software version: UGREEN OS 1.11.0.43.
Actions already taken:
– Deleted and recreated the SSD cache multiple times
– Ran SMART tests on both SSDs (results always “Normal”)
– Verified SSD firmware using Samsung Magician (both drives are up to date)
– Rebooted the NAS and rebuilt the cache several times; the issue still reappears after some time
My assumption:
There may be a hardware or driver issue with the NAS M.2 controller, or a compatibility problem between UGREEN OS 1.11.0.43 and the Samsung 990 PRO SSDs.
Has anyone experienced a similar issue or has any suggestions on how to further troubleshoot or resolve this?
Thank you in advance.
