I've had a disk (HGST HUS726060ALA640 - 6TB) throw disk read errors causing the array health report to fail.  Ran extended SMART self-test which passed.  Last SMART test result attached.  Not sure how to read these reports.  I see 3 errors in the SMART Extended Comprehensive Error Log, which seems to indicate Error 10 and an LBA number.

 

Should I replace this disk?  Its the Parity disk and the newest disk in my array.

 

This is the alert I get in email:

Event: Unraid Status
Subject: Notice [HUNTERNAS] - array health report [FAIL]
Description: Array has 13 disks (including parity & cache)
Importance: warning

Parity - HGST_HUS726060ALA640_AR11021EHJAHKB (sdc) - active 33 C (disk has read errors) [NOK] Disk 1 - ST4000DM000-1F2168_W30086L5 (sdl) - active 38 C [OK] Disk 2 - Hitachi_HDS5C3020ALA632_ML0220F31HKTDN (sdd) - standby [OK] Disk 3 - Hitachi_HDS5C3020ALA632_ML0220F30M33ZD (sde) - standby [OK] Disk 4 - Hitachi_HDS5C3020ALA632_ML0220F30MWAYD (sdf) - active 35 C [OK] Disk 5 - ST5000DM000-1FK178_W4J0YEEN (sdg) - active 36 C [OK] Disk 6 - Hitachi_HUA723030ALA640_MK0371YVG9PYUA (sdj) - active 40 C [OK] Disk 7 - Hitachi_HDS5C3020ALA632_ML0220F30YS4XD (sdk) - standby [OK] Disk 8 - Hitachi_HUA723030ALA640_MK0373YVHH0A4C (sdh) - active 41 C [OK] Disk 9 - Hitachi_HUA723030ALA640_MK0361YHJ0N8JD (sdi) - active 42 C [OK] Disk 10 - Hitachi_HDS5C3020ALA632_ML0220F311GHND (sdn) - standby [OK] Disk 11 - ST5000DM000-1FK178_W4J0B3G1 (sdm) - active 34 C [OK] Cache - Samsung_SSD_850_EVO_500GB_S2RANX0H811137T (sdb) - active 31 C [OK]

Parity is valid
Last checked on Mon 18 Nov 2019 09:02:01 AM CST (yesterday), finding 0 errors.
Duration: 17 hours, 31 minutes, 36 seconds. Average speed: 95.1 MB/s

 

hunternas-smart-20191119-0106.zip

That's not usually a disk problem, but keep monitoring, if you can replace/swap cables to rule them out.