Drobo Gen 3, Failed Drive, Reboot during rebuild

Hi All,

Before I drop $50 on DroboHelp which I’m less than enthusiastic about, I thought I’d ask here.

I have a Drobo Gen3, one of the drives failed in it two days ago. It went into protection mode, then during that, it rebooted. And rebooted again. It starts protection for a few minutes, then reboots. I reseated the rest of the drives, and was randomly getting “no drive” warnings. So, I used some compressed air and blew it all out, and got the drives that weren’t failed back inline.

New drive arrived, I pulled the bad drive to see if that would get it going. Same thing. Starts protection, stalls, and reboots. I haven’t put the new drive in yet since I don’t know if that would risk data loss (if it’s doing a re-layout and reboots, that seems worse than if it’s just in protection mode).

Of course, I submitted a ticket to support, and a diag, and got a response back “you’re out of warranty, buy a drobohelp incident”. I’m… apprehensive about that. All told I own or manage about 10 drobo devices. And when they work it’s great. When they don’t, the blackbox aspect really bugs me. And they used to be good about supporting stuff outside warranty. Guess not anymore.

Anyway, anyone got any ideas before I drop another $50 on this?

Hate to revive this oooold thread but were you able to solve this problem? I’ve encountering this now, with my Drobo 3rd gen. Comes up fine, when it starts protection mode, it stalls - then reboots.

Hi there Mark.

Yes, I got it working. I was able to get through to support. The issue required finding the failing drive, and doing a block level clone to a new drive of the same size. Here’s the instructions they provided.

Basically, the drive is only partially failing such that it crashes the rebuild, but doesn’t come up as failed. Hopefully you’re able to see which one is failing.

1. Whether you have the drive professionally cloned or clone it yourself you will need to flush the Drobo’s internal cache for that drive as follows :

  • With the Drobo powered off eject all of the drives EXCEPT the drive to be cloned.
  • Power the Drobo on
  • Once the Dashboard recognizes Drobo, use Shutdown in Drobo Dashboard > Tools to Shutdown Drobo.

Note: Please ignore any warnings about too many hard drives removed.

2. Cloning :
If you decide to proceed with cloning the drive yourself, you will need;

  • A known good drive that is the same capacity as the problem drive.
  • Make sure there is no data that you need on this new drive as it will be overwritten during the cloning process.
  • To clone the problem drive you will need to connect new drive and problem drive to free (empty) drive bays in your computer or into external drive docks that can be attached to the computer.
  • Do not format or initialize the drives .
  • You will need software that is capable of performing a block level clone. (You can use any cloning software that can-do block level clones and supports drives larger than 1TB.)
  • For Mac, we suggest that you download and install the DEMO version of Data Rescue 3 . Instructions for using the software can be found here:

Note : The cloning process can sometimes take hours or several days to complete depending on the condition of the problem drive.

3. Once the cloning process is successful ;

  • Power on the Drobo without drives installed.
  • Go to Drobo Dashboard > Tool and do key stroke command:
  • Put Drobo into Read Only Mode as follows:

Simultaneous Keystroke command :


Restart the Drobo as prompted from Dashboard, if not prompted power off the Drobo using toggle switch on back of Drobo then power back on.

  • After the Drobo has restarted go to Drobo Dashboard and verify that you see RO next to the name of the Drobo in the Status tab.
  • Once RO has been verified, power the Drobo off
  • If not in RO mode, do NOT proceed
  • If in RO mode, Insert the good cloned drive into Drobo along with the remaining original hard drives
  • Power on the Drobo

I’ll just add, make sure any replacement drive is not only the same capacity, but also CMR - don’t get caught out by an SMR drive. (Beware of WD Red 6TB or less, they changed technology).

For cloning, if you have access to Linux ddrescue (package name gddrescue) should work just fine, but make completely certain you have the source & target correct… dd (and variants such as ddrescue & gddrescue) are not nicknamed data-destroyer for nothing.


Yup. Red Plus drives are CMR as well.

In my case, I borrowed a drive from work, cloned my failing drive to it. Let the drobo rebuild with that temp drive, then swapped it for a replacement drive that I ordered, and let it rebuild again.

Anyway, good luck sir!

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Great! Thanks for the detailed instructions and the pro tips. This is exactly what I needed to know :+1:

Another success story, all greens. Thanks everyone!

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Awesome, thanks for the follow up!