Drobo 2nd Gen no longer mounting after adding 3TB WD Red, shows in daasboard

My former arrangement was 1 TB, 3 x 2 TB. As I was running low on space and got a warning relating to that, so I replaced the 1TB with a 3TB WD Red NAS ready HDD from Amazon. After about 2-3 days of rebuilding, the drobo no longer showed up on my finder/desktop. However I can see it on Drobo Dashboard.

Looking through the info on the dashboard, it show’s the filesystem as ‘not formatted’. The drobo was working fine before this 3TB drive, and I thought when adding new drives, they are automatically formatted. Max capacity is set at 16TB

The dashboard still shows the correct amount of used and free space, so anyone know how i can access the data on it to at least get the data off of it, in case I wanted to do a re-format? Or somehow fix this issue?

Would love to hear any opinions on this matter.


I’m having a similar issue. 2nd Gen Drobo. One drive needed to be changed because it was full. Had 4 1TB WD Blacks, replaced one with a 3TB WE Black and has been rebuilding for 12 hours. Flashing Red or yellow and green.

In my case, neither dashboard or finder shows the device.

With originally 4TB of drives (4x 1TB) should it be taking this long? Anyone have experience? Should I consider this support post http://goo.gl/yMVZB8



12 hours is not long considering the average time it takes. I don’t believe the amount of time it takes is dependant on HDD capacity but rather how much data is on the drobo as a whole, that is a drobo with 4TB of used space will take considerably longer (perhaps days) than a drobo with only 1TB of used space, regardless of how much free space there is.

When i put in the 3TB, it took 3 days before all the lights turned green.

I have Drobo 2nd Gen also: I replaced a full 1 TB drive with a 2 TB drive on Thursday evening. It is now Sunday and all lights continue to flash between green and orange. I have no idea how to resolve this or even where to look!

What does your drobo dashboard show? It should given an estimate of how long reorganising data should take

Yes, I think some critical guidance is missing from this in terms of letting people know how long their Drobo will be working on Data Protection, Rebalancing. This could easily be explained here on these help forums or even included in the documentation.

My 4x 1TB (and they are full) Drobo 2ndG is going to take 83 HOURS!

So this was a number way off - my expectation. Thats ok, now I know. It would help if this would have been published - some sort of baseline. Everyone has their own view of how long is “LONG”

Bottom line - don’t unplug because your Drobo could be doing this for DAYS.

Hope this helps someone else.

Mine just finished, took over 3+ days, and then it goes and shows the dreaded red light. Shut down my computer, changed to USB interface and it was done in 10 hours!

Still doesn’t show up in finder though!!

That can be frustrating. Do you get the Dashboard? I have this problem a lot - my drobo is connected via FW800 and often FINDER sees it but the dashboard doesn’t.

I’ve just added a new WD3TB Black to replace and it says a 48hr wait. Hoping to avoid the red light.

I can always see the device fine in dashboard. All i want to do now is to salavage the data off of the drobo and never use it again! Been doing some research on Synology

Ok, I’m back. Added the new WD3TB Black and now it states: “Red Alert. Drobo is critically low on capacity. Replace the hard drive by the red light with a larger capacity drive.”

That can’t be correct can it? Do I need to reboot this? I just added 50% more drive capacity.

I had 4 2TB drives and replaced one with a 3TB. IT originally said that it was going to take 235hrs. I’ve had to disconnect my laptop and shut the drobo down as recommend in an article on the drobo site. I’ve now started again and it is saying 89 hours.
I’m getting the impression from this thread that this is normal?


One thing I learnt was to not trust that ETA for how long it’ll take

I have the same problem. Rebuilt for 54 hours, shows up fine in Dashboard, but can’t mount.
OS X disk repair fails, and the suggested DiskWarrior just keeps ‘Searching for Volume Information’.


My problem was similar, but I do notice that when you add a 3TB drive, especially if upgrading from 1TB drives, there seems to be a problem.

I had 5 x 1TB WD Black drives, and I upgraded the drives and when I put in the 3TB drive, all the problems began. When I added a 2TB and a 4TB, no problem at all? I wonder if the 3TB size throws off the internal array configs, and it has to redo all the arrays, while maintaining your data, which is why it takes so long?


Interesting theory, first I’ve heard. After you noticed the problem, were you able to fix it?

hi guys, in terms of upgrades and rebuilding times, theres some handy info in one of the threads i posted in the past about an upgrade i did:

just shows you all the things i had to do (or think about) when planning an upgrade.

it might have some useful info for you, inlcuding times from yoyoma on page 2, but theres a lot of info there lol :slight_smile: