I'm on 6.11.5. A few days ago I found that overnight my disk 4 was in an error state "No device identification ()" and shortly after that there had been a write error and the disk had been disabled. So I rebuilt, without incident, and all seemed fine. But this morning, about a day after the rebuild, there was a read error.

 

From my amateur's view of the diagnostics, the disk looks OK, but obviously I'm worried about the errors. Does the disk need to be replaced?

tower-diagnostics-20230730-0935.zip

Looks more like a power/connection problem, try replacing the cables.

My server seems to be a bit sensitive - meaning that cables seem intermittently to come a little loose (UDMA CRC errors). So generally I avoid opening up the case unless absolutely necessary. So here I just rebooted the server without touching anything inside, and everything has been working fine for a few weeks now (I've probably now jinxed the server). So I'll put it down to a connection problem.