After months of stability, I noticed a red ball beside one of the drives this morning. I checked the syslog (attached) numerous errors on disk 13, and also that the syslog had been restarted for some reason this morning (I have not restarted the array in a couple of months). I then ran a smart report (attached) and noticed that the value for Current_Pending_Sector is 54. Any suggestions on how to proceed?

Cheers

Rebuild the drive in place: Start the array with the drive unassigned and the restart the array with the drive assigned. Do a parity check after the rebuild. The post a new SMART report.

Thanks for your suggestion. I'm wondering now if the drive is actually still spinning. When I tried to access the files on it, the video file played properly, but after a refresh of the browser page, the red ball beside the drive is still flashing, which to me indicates that it did not spin up, and that the video being played was the backup copy. I wonder if something more serious is going on.

The disk is disabled and will not spin. Data is being generated by the other disks and parity. Loss of a second drive will result in data loss.

Thanks for your reply. The array had not yet been stopped when I attempted to access the drive in question. Are you saying that while the array is still running, unRaid will disable a drive that has errors, and use data is being generated by the other disks and parity? Sorry, I don't quite understand.

Yes. This is the point of parity protection. The data from a single failed disk is still available. The same method is used rebuild the contents of the failed disk. A second failure will result in data loss.

I replaced the drive with a spare and let unRaid rebuild - then ran WD's Data Lifeguard Diagnostic in Windows. It failed the quick test, so it's now on its way to WD for replacement. Thankfully, it was still under warranty.

Cheers