Dual Redundancy on my DROBO

Hi Everyone,

My current DROBO PRO has 10.63 TB of data on it and I have 8 2 TB drives. I checked on Drobolator and it showed that a dual redundant Drobo Pro can hold 10.89 TB of data. However, on my pro, I have less than that and one of the drive lights is yellow asking me to replace a drive AND Drobo Dasboard won’t let me check the option for Dual Redundancy.

So how much data can I really put on a dual redundancy enabled Pro?


you can put that amount of data on there…

but you cant enable dual disk redundancy if it will immediately take you to a low space condition

if you took some data off, you could enable dual disk redundancy

then put the data back on - even though that will mean you then start getting low space warnings

Thanks for the information. I did as you said and it’s going to Dual Redundancy now but it’s going to take 112 hours.

I wasn’t expecting it to take that long. In that case I would just have preferred to format the whole thing, set it to dual redundancy and then copied everything on there.

This is my Drobo Pro that backs up my original Drobo Pro so I did it the wrong way by copying the data on it first and then checking dual redundancy instead of the other way around.

After 4 hours, the timer just indicated that it will take 112 hours. So it’s still the same time after 5 hours.

are you using it at all - it shouldn’t take that long, but using it will dramatically increase the time

No I’m not using it at all. It still says 112 hours and this is after leaving it alone for one night.

In looking back at anything I might have done. I remember switching out a 1 TB drive for 2 TB drives and while it had started the process of protecting, I clicked the Dual box.

Could that have caused the problem?

How do I fix it now? I’m not concerned about the data on it as that’s my back up copy and I can just re back it up.

Can’t say for certain but I tend to like to let things settle before changing other things. :slight_smile: (Meaning I’d have let it finished rebuilding the array after installing the 2TB drive and then clicked dual redundancy.)

You don’t say how your Drobo is connected so my (very) rough guess is that it’d take 56 hours to push 10TB back onto it after reformatting. If it’s FW800 then it could be 90+ hours.

Yeah, that’s why

Usually to move up to dual disk redundancy it only has to create one lot of parity

Since it was already degraded when you turned on Dual it’s having to create two lots of parity. So it will naturally take twice as long!

Thanks for the responses, for some reason I thought if I checked it it would just do them both together.

It’s down to 172 hours now so I guess I’ll just wait a week for it to finish.

it is doing them both together, but its still twice as much work!