I hate it when this happens… It looks like a 4TB drive in my 5-bay Drobo has gone out. Drobo cannot detect it. I have dual-drive redundancy enabled, so two drives can fail and I’d still have my data… Fortunately.
Hopefully, I won’t have two drives fail between now and the time my replacement drive arrives. :)
On the plus, drive prices have dropped since I bought these drives in 2019. I’ll begin the process of upgrading drives to 6TB models over coming months, money permitting.