I sent this to Drobo’s support but they provided me with an irrelevant/useless response.
My Drobo has 4x4TB hard drives in it which I believe is the maximum supported for this model. It is nearly full; as of this writing I have about 1.2TB free space. Drobo Dashboard is telling me that I need to “replace the drive indicated by the yellow light with a larger capacity drive” and shows a yellow status in Dashboard (see attached screen capture). HOWEVER, as I understand it I cannot add a larger capacity drive to this unit, and more importantly the Drobo itself is showing a RED light next to the top bay which would indicate a drive failure. Therefore: (1) Can this unit support larger HDs (e.g., 6TB)? (2) Why is it showing yellow in Dashboard and red on the unit? (3) Which is correct, “yellow-capacity reaching max” or “red-drive failing”? How can I find out which is REALLY happening?