Drobo

Can't change from single to dual redundency

I currently have 4 2TB drives in my drobo.

I’ve used 1.97TB of storage.

I’d like to move from single to dual, but, when I click the box it tells me I need to add another drive. That seems odd since even after I migrate to dual, I’ll only be using ~50% capacity…

Anyone know how to fix this?

David

Hi DrDavid,
if i understand “single” drive redundancy correctly, a rough plan of 4x2TB drives, means you have approx 3x2TB of usable space. eg you lose your largest drive to redundancy/security etc. = approx 6TB usable.

(Usually you also lose a bit more for normal formatting etc. so its probably more like 5.5TB usable or similar)

Now if i understand “dual” drive redundancy correctly, a rough plan of 4x2TB drives, means you have approx 2x2TB of usable space. (eg losing your 2 largest drives worth, to redundancy/security etc). = approx 4TB usable.

(if the usual formattating takes up a bit more space, that probably leaves you with around 3.8TB usable).
exact figures will be more accurate via that drobolator calculator but these are just approximations.

In this example i was hoping to be able to point out that 1.9TB cant fit twice into 3.8TB but im now puzzled myself LOL - :smiley: