brankko

What happened here is not enough power from PSU.

Let me explain.
I started having Disk (read) errors on one of the larger drives. I replaced the drive, got the same thing after some time.
I changed the cables... the same... it works for days and then it detects some errors and disables the disk.

As I was adding the drives, I kept adding those SATA extender adapters and at some point it was too much for poor PSU.

I tried a different PSU and it all worked as a clock. Since I already started building second backup server, I reduced the number of drives in this machine and replaced smaller drives with larger. Now it works with the old PSU as well. It's weird because it's not obvious, but it makes sense. So people, be careful with your power load on a single branch of PSU.