5N2 Doesn't Recognize New Drive

I’ve had a working 5N2 since last year; one of my older 2TB WD SATA drives failed, so I waited for the data protection to be complete, and swapped in a new WD 4TB, same model as is currently operating correctly in one of the bays.

However the Drobo won’t recognize the new drive - just says the bay is empty. Tried a second new HDD - same result.

Any ideas? My experience with Drobo support to-date has been poor; this unit is still under warranty so I have logged a case, but I’m not at all hopeful.

Thanks in advance for any suggestions,


Was your ‘new’ WD 4TB a shingled-drive? because Drobo does not recommend them.

Thanks for the response - but how do I determine if it is a singled-drive?

It’s the same WD Model as is currently working correctly in another bay.


If you can look at your receipt it should have the model and serial number. Go online and do a quick search.
Or, pull it out of the array to access the serial number (since it is not registering with your drobo)

Maybe this link will help with identification:
WD Sets the Record Straight: Lists All Drives That Use Slower SMR Tech | Tom’s Hardware

Well, it’s a 4TB WD Blue Model WD40EZRZ. From the table it could be either???

Looks like your WD40EZRZ is CMR not SMR:

So that rules that out.
Have you tried removing and reinserting the new drive “solidly” (I note you have 2 drives you have tested) - still, sometimes the seating is not fully aligned and therefore the drive is not being read as loaded?
As an aside, I would be recommending, if not done already, an immediate external backup copy be made of your data.