I was already on 1.1.2 which was supposed to support 3TB.
Apparently when I swapped out my 2TB for 3TB, drobo FS did not like it and once the 3TB was flagged as a failed drive, drobo locks out that 3TB drive by serial number. I don’t know the reason why I was not able to swap from a lower size drive to a bigger size drive.
In order for me to get the 3TB to work was to do a factory reset. It of course that wiped out all of the data so I had to start from scratch. I did backup my data to another NAS which took a couple of days, prior to trying out the factory reset.
My fear is that in the future, should I swap out a smaller drive for a bigger drive, I might experience a similar problem and would be a pain to resolve with so much data at that point.
So lesson learned is drobo may sometimes incorrectly reject a good drive (in my case 2 good drives) and lock it out from that drobo. Many stories of similar experiences from other places I read.
That’s great you got it to work. Thanks for sharing so others might be able to get a faster resolve if this happens to them. I take it that you now have the 3TB Coolspin working properly in your DroboFS?