I'm doing my monthly parity check and two disks came up with read errors. The disks in question are WCC4E3KLD62L and WMC5D085LR2. The first disk has 123 read errors and the second disk has 1 read error.  The first disk is complaining about READ DMA EXT, the second disk is complaining about READ FPDMA QUEUED, CHECK POWER MODE,  CHECK POWER MODE,  SMART READ ATTRIBUTE THRESHOLDS [OBS-4] and  SMART READ DATA.

 

Diagnostics attached.terrabyteme-diagnostics-20200501-1514.zip

Both are logged as actual disk problems, but these errors can sometimes be intermittent, you should run an extended SMART test on both, or another parity check (non correcting)

Thanks, the one disk did show read errors before and then disappeared. I bought a replacement disk, but I did not know which disk had shown the read errors. I realize now that I could have looked at the Archive to see the errors. 

WCC4E3KLD62L failed the extended SMART test, fortunately the other drive passed. The array is happily rebuilding now (hopefully), as I already had a pre-cleared spare.

 

I'm  wondering if anyone schedules their SMART tests or do you just replace your disks on a schedule?

 

Parity check accomplishes the same as an extended SMART test, so as long as it's regularly done, like once a month, it will catch any issues.