Drobo 5N2 drive replacement issue

Hello all,

I’m having a really strange problem. My Drobo 5N2 was low on space and was asking me to replace the smallest drive, in bay 4 (the bottom-most bay) . I had the following drives in my Drobo:

Bay 0: WD Gold 16TB
Bay 1: WD Gold 16TB
Bay 2: 14TB (don’t remember model)
Bay 3: 14TB (don’t remember model)
Bay 4: Seagate Ironwolf Pro 10TB

Since I was down to 12% of my ~49TB volume, I replaced the 10TB drive with a Seagate Exos 18TB (ST18000NM000J), which I had previously upgraded to the latest firmware that enables 4kn (and Drobo supposedly supports). Upon replacing the drive, all the lights are flashing green and yellow. I believe this is the sequence when in “Data Protection mode” and the array is rebuilding itself. The blue LEDs at the bottom are lit at 8 of 10.

I have recently upgraded to firmware 4.3.1 (before it was seemingly pulled by Drobo). Since upgrading the firmware, I have successfully performed a rebuild (replaced drive), though it did take nearly a week to complete.

Now is the weird part. My Drobo is no longer seen by Drobo Dashboard. I can ping the Drobo. I can access the filesystem from my computers and mobile devices. I can see the directory structure of most of my directories. But when I go into those directories, they are all empty (and they obviously shouldn’t be). When I try to connect via SSH (which I used to do regularly), I get “Connection refused”.

I have 42TB of data on my Drobo. I’d very much like to not lose it. Has anyone ever experienced something similar? If so, how did you restore service? Can I shut down and restart Drobo while in this state to see if things get fixed? Should I try to put back the old drive, or will this trigger Drobo to create a new volume? I’m kinda paralyzed with respect to what I can safely do as I’ve never seen this behaviour before.

Any help would be appreciated! Thank you!



Hello there!

With the help of Drobo Support, I was able to work through my issue. Here is what I did:

  • I shut down my Drobo by hitting the power button. (Drobo support at first was hesitant to tell me to do this since Drobo was seemingly in Data Protection mode, but there was no other option)

  • I removed the power adapter

  • I removed all drives

  • I plugged in the power adapter and turned on Drobo with no drives

  • I waited until Drobo was recognized by the Dashboard

  • I placed Drobo into RO (Read Only) Mode: double-click the Drobo icon and press CTRL-ALT-SHIFT-R in Windows or CTRL-OPTION-SHIFT-R in MacOS

  • I was immediately presented with the prompt that Drobo was placed into RO Mode:

  • After a few moments, I was prompted to reboot:

  • I made sure that Drobo was really in RO Mode after the reboot:

  • I took a diagnostic to send to Drobo support:


  • I shutdown Drobo via the Dashboard
  • I unplugged Drobo and reinserted all my drives
  • I started Drobo and waited for it to be recognized by the Dashboard
  • Drobo is now in RO mode; my files are accessible. I proceeded to backup any data that wasn’t already backed up
  • Once backup was complete, I shutdown Drobo via the Dashboard
  • I unplugged Drobo, removed all drives, plugged Drobo and booted up again
  • I put Drobo back into RW (Read/Write) Mode: double-click the Drobo icon and press CTRL-ALT-SHIFT-R in Windows or CTRL-OPTION-SHIFT-R in MacOS
  • After rebooting and verifying that Drobo was no longer in RO Mode (the “(RO)” will disappear next to your Drobo’s name), I shutdown via the Dashboard
  • I removed the power adapter, reinserted all my drives, and booted up again
  • I waited and eventually Drobo became available in Dashboard and immediately went into Data Protection

All is well again. For reference, when the issue first occurred, I left Drobo sitting overnight and it was never recognized by Dashboard. When I followed the above process, Drobo was up and running within 15-ish minutes. It might have come back to life after a simple reboot, but I prefered to take no chances and backup my data, just in case. I also thought the instructions I posted might be of use to some future forum user. :slight_smile:

Now I just have to wait for the Data Protection to complete. Big thanks to Ed S from Drobo support for guiding me through this ordeal (despite being out of warranty).